428 results
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2. Phase portraits of separable quadratic systems and a bibliographical survey on quadratic systems
- Author
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Jaume Llibre and Tao Li
- Subjects
Pure mathematics ,Class (set theory) ,Poincaré compactification ,Phase portrait ,General Mathematics ,010102 general mathematics ,Quadratic function ,01 natural sciences ,Separable space ,Quadratic system ,symbols.namesake ,Quadratic equation ,Separable system ,Poincaré conjecture ,symbols ,Compactification (mathematics) ,0101 mathematics ,Quadratic differential ,Mathematics - Abstract
Although planar quadratic differential systems and their applications have been studied in more than one thousand papers, we still have no complete understanding of these systems. In this paper we have two objectives. First we provide a brief bibliographical survey on the main results about quadratic systems. Here we do not consider the applications of these systems to many areas as in Physics, Chemist, Economics, Biology, … Second we characterize the new class of planar separable quadratic polynomial differential systems. For such class of systems we provide the normal forms which contain one parameter, and using the Poincare compactification and the blow up technique, we prove that there exist 10 non-equivalent topological phase portraits in the Poincare disc for the separable quadratic polynomial differential systems.
- Published
- 2021
3. On the singular value decomposition over finite fields and orbits of GU×GU
- Author
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Robert M. Guralnick
- Subjects
Pure mathematics ,General Mathematics ,010102 general mathematics ,010103 numerical & computational mathematics ,01 natural sciences ,Unitary state ,Nilpotent matrix ,symbols.namesake ,Finite field ,Character (mathematics) ,Kronecker delta ,Singular value decomposition ,Linear algebra ,symbols ,0101 mathematics ,Algebraic number ,Mathematics - Abstract
The singular value decomposition of a complex matrix is a fundamental concept in linear algebra and has proved extremely useful in many subjects. It is less clear what the situation is over a finite field. In this paper, we classify the orbits of GU m ( q ) × GU n ( q ) on M m × n ( q 2 ) (which is the analog of the singular value decomposition). The proof involves Kronecker’s theory of pencils and the Lang–Steinberg theorem for algebraic groups. Besides the motivation mentioned above, this problem came up in a recent paper of Guralnick et al. (2020) where a concept of character level for the complex irreducible characters of finite, general or special, linear and unitary groups was studied and bounds on the number of orbits was needed. A consequence of this work determines possible pairs of Jordan forms for nilpotent matrices of the form A A ∗ and A ∗ A over a finite field and A A ⊤ and A ⊤ A over arbitrary fields.
- Published
- 2021
4. Null controllability of semi-linear fourth order parabolic equations
- Author
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K. Kassab, Laboratoire Jacques-Louis Lions (LJLL (UMR_7598)), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)
- Subjects
Null controllability ,Observability ,Global Carleman estimate ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,Null (mathematics) ,Exact controllability ,01 natural sciences ,Parabolic partial differential equation ,Dirichlet distribution ,Domain (mathematical analysis) ,010101 applied mathematics ,Controllability ,symbols.namesake ,Linear and semi-linear fourth order parabolic equation ,Bounded function ,MSC : 35K35, 93B05, 93B07 ,Neumann boundary condition ,symbols ,[MATH]Mathematics [math] ,0101 mathematics ,Mathematics - Abstract
International audience; In this paper, we consider a semi-linear fourth order parabolic equation in a bounded smooth domain Ω with homogeneous Dirichlet and Neumann boundary conditions. The main result of this paper is the null controllability and the exact controllability to the trajectories at any time T > 0 for the associated control system with a control function acting at the interior.; Dans ce papier, on considère uneéquation parabolique semi-linéaire de quatrième ordre dans un domaine borné régulier Ω avec des conditions aux limites de type Dirichlet et Neumann homogènes. Le résultat principal de ce papier concerne la contrôlabilitéà zéro et la contrôlabilité exacte pour tout T > 0 du système de contrôle associé avec un contrôle agissantà l'interieur.
- Published
- 2020
5. Boundary value problems for the Brinkman system with L∞ coefficients in Lipschitz domains on compact Riemannian manifolds. A variational approach
- Author
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Wolfgang L. Wendland and Mirela Kohr
- Subjects
Pure mathematics ,Applied Mathematics ,General Mathematics ,Weak solution ,010102 general mathematics ,Mathematics::Analysis of PDEs ,Fixed-point theorem ,Riemannian manifold ,Lipschitz continuity ,01 natural sciences ,Dirichlet distribution ,Physics::Fluid Dynamics ,010101 applied mathematics ,Sobolev space ,Nonlinear system ,symbols.namesake ,symbols ,Boundary value problem ,0101 mathematics ,Mathematics - Abstract
The purpose of this paper is to show well-posedness results in L 2 -based Sobolev spaces for transmission, Dirichlet, Neumann, and mixed boundary value problems for the Brinkman system with L ∞ coefficients in Lipschitz domains on a compact Riemannian manifold of dimension m ≥ 2 . The Dirichlet, transmission, and mixed problems for the nonlinear Darcy-Forchheimer-Brinkman system with L ∞ coefficients are also analyzed. First, we focus on the well-posedness of linear transmission, Dirichlet and mixed boundary value problems for the Brinkman system with L ∞ coefficients in Lipschitz domains on compact Riemannian manifolds by using a variational approach that reduces such a boundary value problem to a mixed variational formulation defined in terms of two bilinear continuous forms, one of them satisfying a coercivity condition and another one the inf-sup condition. Further, we show the equivalence between each boundary value problem for the Brinkman system with L ∞ coefficients and its mixed variational counterpart, and then the well posedness in L 2 -based Sobolev spaces by using the Necas-Babuska-Brezzi technique. The second goal of this paper is the construction of the Newtonian and layer potential operators for the Brinkman system with L ∞ coefficients in Lipschitz domains on compact Riemannian manifolds by using the well-posedness results for the analyzed linear transmission problems. Various mapping properties of these operators are also obtained and used to describe the weak solutions of the Poisson problems with Dirichlet and Neumann conditions for the nonsmooth Brinkman system in terms of such potentials. Finally, we combine the well-posedness results of the Poisson problems of Dirichlet, transmission, and mixed type for the nonsmooth Brinkman system with a fixed point theorem in order to show the existence of a weak solution of the Poisson problem of Dirichlet, transmission, or mixed type for the (nonlinear) Darcy-Forchheimer-Brinkman system with L ∞ coefficients in L 2 -based Sobolev spaces in Lipschitz domains on compact Riemannian manifolds of dimension m ∈ { 2 , 3 } .
- Published
- 2019
6. Convergence of boundary layers for the Keller–Segel system with singular sensitivity in the half-plane
- Author
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Qianqian Hou and Zhi-An Wang
- Subjects
Plane (geometry) ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,Prandtl number ,Boundary (topology) ,Space (mathematics) ,01 natural sciences ,010101 applied mathematics ,Boundary layer ,symbols.namesake ,symbols ,Boundary value problem ,0101 mathematics ,Layer (object-oriented design) ,Degeneracy (mathematics) ,Mathematics - Abstract
Though the boundary layer formation in the chemotactic process has been observed in experiment (cf. [63] ), the mathematical study on the boundary layer solutions of chemotaxis models is just in its infant stage. Apart from the sophisticated theoretical tools involved in the analysis, how to impose/derive physical boundary conditions is a state-of-the-art in studying the boundary layer problem of chemotaxis models. This paper will proceed with a previous work [24] in one dimension to establish the convergence of boundary layer solutions of the Keller–Segel model with singular sensitivity in a two-dimensional space (half-plane) with respect to the chemical diffusion rate denoted by e ≥ 0 . Compared to the one-dimensional boundary layer problem, there are many new issues arising from multi-dimensions such as possible Prandtl type degeneracy, curl-free preservation and well-posedness of large-data solutions. In this paper, we shall derive appropriate physical boundary conditions and gradually overcome these barriers and hence establish the convergence of boundary layer solutions of the singular Keller–Segel system in the half-plane as the chemical diffusion rate vanishes. Specially speaking, we justify that the boundary layer converges to the outer layer (solution with e = 0 ) plus the inner layer as e → 0 , where both outer and inner layer profiles are precisely derived and well understood. By doing this, the structure of boundary layer solutions is clearly characterized. We hope that our results and methods can shed lights on the understanding of underlying mechanisms of the boundary layer patterns observed in the experiment for chemotaxis such as the work by Tuval et al. [63] , and open a new window in the future theoretical study of chemotaxis models.
- Published
- 2019
7. Reproducing kernel orthogonal polynomials on the multinomial distribution
- Author
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Robert C. Griffiths and Persi Diaconis
- Subjects
Numerical Analysis ,Stationary distribution ,Markov chain ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,Poisson kernel ,010103 numerical & computational mathematics ,Kravchuk polynomials ,01 natural sciences ,Combinatorics ,symbols.namesake ,Kernel (statistics) ,Orthogonal polynomials ,symbols ,Test statistic ,Multinomial distribution ,0101 mathematics ,Analysis ,Mathematics - Abstract
Diaconis and Griffiths (2014) study the multivariate Krawtchouk polynomials orthogonal on the multinomial distribution. In this paper we derive the reproducing kernel orthogonal polynomials Q n ( x , y ; N , p ) on the multinomial distribution which are sums of products of orthonormal polynomials in x and y of fixed total degree n = 0 , 1 , … , N . The Poisson kernel ∑ n = 0 N ρ n Q n ( x , y ; N , p ) arises naturally from a probabilistic argument. An application to a multinomial goodness of fit test is developed, where the chi-squared test statistic is decomposed into orthogonal components which test the order of fit. A new duplication formula for the reproducing kernel polynomials in terms of the 1-dimensional Krawtchouk polynomials is derived. The duplication formula allows a Lancaster characterization of all reversible Markov chains with a multinomial stationary distribution whose eigenvectors are multivariate Krawtchouk polynomials and where eigenvalues are repeated within the same total degree. The χ 2 cutoff time, and total variation cutoff time is investigated in such chains. Emphasis throughout the paper is on a probabilistic understanding of the polynomials and their applications, particularly to Markov chains.
- Published
- 2019
8. Superconvergence of kernel-based interpolation
- Author
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Robert Schaback
- Subjects
Numerical Analysis ,Applied Mathematics ,General Mathematics ,Open problem ,Hilbert space ,Numerical Analysis (math.NA) ,010103 numerical & computational mathematics ,Positive-definite matrix ,Superconvergence ,Eigenfunction ,01 natural sciences ,010101 applied mathematics ,symbols.namesake ,Spline (mathematics) ,FOS: Mathematics ,symbols ,Applied mathematics ,Mathematics - Numerical Analysis ,Boundary value problem ,0101 mathematics ,Spline interpolation ,Analysis ,Mathematics - Abstract
From spline theory it is well-known that univariate cubic spline interpolation, if carried out in its natural Hilbert space W 2 2 [ a , b ] and on point sets with fill distance h , converges only like O ( h 2 ) in L 2 [ a , b ] if no additional assumptions are made. But superconvergence up to order h 4 occurs if more smoothness is assumed and if certain additional boundary conditions are satisfied. This phenomenon was generalized in 1999 to multivariate interpolation in Reproducing Kernel Hilbert Spaces on domains Ω ⊂ R d for continuous positive definite Fourier-transformable shift-invariant kernels on R d . But the sufficient condition for superconvergence given in 1999 still needs further analysis, because the interplay between smoothness and boundary conditions is not clear at all. Furthermore, if only additional smoothness is assumed, superconvergence is numerically observed in the interior of the domain, but a theoretical foundation still is a challenging open problem. This paper first generalizes the “improved error bounds” of 1999 by an abstract theory that includes the Aubin–Nitsche trick and the known superconvergence results for univariate polynomial splines. Then the paper analyzes what is behind the sufficient conditions for superconvergence. They split into conditions on smoothness and localization, and these are investigated independently. If sufficient smoothness is present, but no additional localization conditions are assumed, it is numerically observed that superconvergence always occurs in the interior of the domain, and some supporting arguments are provided. If smoothness and localization interact in the kernel-based case on R d , weak and strong boundary conditions in terms of pseudodifferential operators occur. A special section on Mercer expansions is added, because Mercer eigenfunctions always satisfy the sufficient conditions for superconvergence. Numerical examples illustrate the theoretical findings.
- Published
- 2018
9. Conservation of a predator species in SIS prey-predator system using optimal taxation policy
- Author
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Nishant Juneja and Kulbhushan Agnihotri
- Subjects
Hopf bifurcation ,Equilibrium point ,Biomass (ecology) ,education.field_of_study ,General Mathematics ,Applied Mathematics ,Population ,General Physics and Astronomy ,Statistical and Nonlinear Physics ,01 natural sciences ,010305 fluids & plasmas ,Predation ,010101 applied mathematics ,symbols.namesake ,0103 physical sciences ,symbols ,Econometrics ,Prey predator ,0101 mathematics ,education ,Predator ,Bifurcation ,Mathematics - Abstract
In this paper, we present and analyze a prey-predator system, in which prey species can be infected with some disease. The model presented in this paper is motivated from D. Mukherjee’s model in which he has considered an SI model for the prey species. There are substantial evidences that infected individuals have the ability to recover from the disease if vaccinated/ treated properly. In this regard, Mukherjee’s model is modified by considering SIS model for prey species. Theoretical and numerical simulations show that the recovery of infected prey species plays a crucial role in eliminating the limit cycle oscillations and thus making the interior equilibrium point stable. The possibility of Hopf bifurcation around non zero equilibrium point using the recovery rate as a bifurcation parameter, is discussed. Further, the model is extended by incorporating the harvesting of predator population. A monitory agency has been introduced which monitors the exploitation of resources by implementing certain taxes for each unit biomass of the predator population. The main purpose of the present research is to explore the effect of recovery rate of prey on the dynamics of the system and to optimize the total economical net profits from harvesting of predator species, taking taxation as control parameter.
- Published
- 2018
10. Computation of the largest positive Lyapunov exponent using rounding mode and recursive least square algorithm
- Author
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Samir A. M. Martins, Márcio J. Lacerda, Márcia L. C. Peixoto, and Erivelton G. Nepomuceno
- Subjects
Logarithm ,Dynamical systems theory ,General Mathematics ,Applied Mathematics ,Computation ,Rounding ,General Physics and Astronomy ,Statistical and Nonlinear Physics ,Lyapunov exponent ,Interval (mathematics) ,01 natural sciences ,Upper and lower bounds ,010305 fluids & plasmas ,symbols.namesake ,0103 physical sciences ,Line (geometry) ,symbols ,Applied mathematics ,010301 acoustics ,Mathematics - Abstract
It has been shown that natural interval extensions (NIE) can be used to calculate the largest positive Lyapunov exponent (LLE). However, the elaboration of NIE are not always possible for some dynamical systems, such as those modelled by simple equations or by Simulink-type blocks. In this paper, we use rounding mode of floating-point numbers to compute the LLE. We have exhibited how to produce two pseudo-orbits by means of different rounding modes; these pseudo-orbits are used to calculate the Lower Bound Error (LBE). The LLE is the slope of the line gotten from the logarithm of the LBE, which is estimated by means of a recursive least square algorithm (RLS). The main contribution of this paper is to develop a procedure to compute the LLE based on the LBE without using the NIE. Additionally, with the aid of RLS the number of required points has been decreased. Eight numerical examples are given to show the effectiveness of the proposed technique.
- Published
- 2018
11. On emergence and complexity of ergodic decompositions
- Author
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Pierre Berger and Jairo Bochi
- Subjects
Pure mathematics ,Lebesgue measure ,Dynamical systems theory ,General Mathematics ,010102 general mathematics ,Dynamical Systems (math.DS) ,Lebesgue integration ,37A35, 37C05, 37C45, 37C40, 37J40 ,01 natural sciences ,Measure (mathematics) ,010104 statistics & probability ,Metric space ,symbols.namesake ,FOS: Mathematics ,symbols ,Ergodic theory ,Mathematics - Dynamical Systems ,0101 mathematics ,Dynamical system (definition) ,Probability measure ,Mathematics - Abstract
A concept of emergence was recently introduced in the paper [Berger] in order to quantify the richness of possible statistical behaviors of orbits of a given dynamical system. In this paper, we develop this concept and provide several new definitions, results, and examples. We introduce the notion of topological emergence of a dynamical system, which essentially evaluates how big the set of all its ergodic probability measures is. On the other hand, the metric emergence of a particular reference measure (usually Lebesgue) quantifies how non-ergodic this measure is. We prove fundamental properties of these two emergences, relating them with classical concepts such as Kolmogorov's $\epsilon$-entropy of metric spaces and quantization of measures. We also relate the two types of emergences by means of a variational principle. Furthermore, we provide several examples of dynamics with high emergence. First, we show that the topological emergence of some standard classes of hyperbolic dynamical systems is essentially the maximal one allowed by the ambient. Secondly, we construct examples of smooth area-preserving diffeomorphisms that are extremely non-ergodic in the sense that the metric emergence of the Lebesgue measure is essentially maximal. These examples confirm that super-polynomial emergence indeed exists, as conjectured in the paper [Berger]. Finally, we prove that such examples are locally generic among smooth diffeomorphisms., Comment: v3: Final version; to appear in Advances in Mathematics
- Published
- 2021
12. Fonctions complètement multiplicatives de somme nulle
- Author
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Eric Saias and Jean-Pierre Kahane
- Subjects
General Mathematics ,010102 general mathematics ,Multiplicative function ,01 natural sciences ,Abelian and tauberian theorems ,010101 applied mathematics ,Combinatorics ,symbols.namesake ,Riemann hypothesis ,Bounded function ,symbols ,Euler's formula ,0101 mathematics ,Invariant (mathematics) ,Well-defined ,Dirichlet series ,Mathematics - Abstract
Completely multiplicative functions whose sum is zero ($CMO$). The paper deals with $CMO$, meaning completely multiplicative ($CM$) functions $f$ such that $f(1)=1$ and $\sum\limits_1^\infty f(n)=0$. $CM$ means $f(ab)=f(a)f(b)$ for all $(a,b)\in \N^{*2}$, therefore $f$ is well defined by the $f(p)$, $p$ prime. Assuming that $f$ is $CM$, give conditions on the $f(p)$, either necessary or sufficient, both is possible, for $f$ being $CMO$ : that is the general purpose of the authors. The $CMO$ character of $f$ is invariant under slight modifications of the sequence $(f(p))$ (theorem~3). The same idea applies also in a more general context (theorem~4). After general statements of that sort, including examples of $CMO$ (theorem~5), the paper is devoted to ``small'' functions, that is, functions of the form $\frac{f(n)}{n}$, where the $f(n)$ are bounded. Here is a typical result : if $|f(p)|\le 1$ and $Re\, f(p)\le0$ for all $p$, a necessary and sufficient condition for $\big(\frac{f(n)}{n}\big)$ to be $CMO$ is $\sum \, Re\, f(p)/p=-\infty$ (theorem~8). Another necessary and sufficient condition is given under the assumption that $|1+f(p)|\le 1$ and $f(2)\not=-2$ (theorem~7). A third result gives only a sufficient condition (theorem~9). The three results apply to the particular case $f(p)=-1$, the historical example of Euler. Theorems 7 and 8 need auxiliary results, coming either from the existing literature (Hal\'asz, Montgomery--Vaughan), or from improved versions of classical results (Ingham, Ska\l ba) about $f(n)$ under assumptions on the $f*1(n)$, * denoting the multiplicative convolution (theorems~10~and~11).
- Published
- 2017
13. Adaptive fuzzy impulsive synchronization of chaotic systems with random parameters
- Author
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Dong Li, Xingpeng Zhang, and Xiaohong Zhang
- Subjects
Lyapunov function ,Adaptive control ,General Mathematics ,Applied Mathematics ,Synchronization of chaos ,Chaotic ,General Physics and Astronomy ,Statistical and Nonlinear Physics ,02 engineering and technology ,01 natural sciences ,Fuzzy logic ,010305 fluids & plasmas ,symbols.namesake ,Nonlinear system ,Control theory ,0103 physical sciences ,Synchronization (computer science) ,0202 electrical engineering, electronic engineering, information engineering ,symbols ,020201 artificial intelligence & image processing ,Randomness ,Mathematics - Abstract
Randomness is a common phenomenon in nonlinear systems. And conditions to reach synchronization are more complex and difficult when chaotic systems have random parameters. So in this paper, an adaptive scheme for synchronization of chaotic system with random parameters by using the fuzzy impulsive method and combining the properties of Wiener process and Ito differential is investigated. The main concepts of this paper are applying fuzzy method to approximate the nonlinear part of system, then using Ito differential to study the Wiener process of random parameters of chaotic system, and realizing synchronization under fuzzy impulsive method. The stability is analyzed by Lyapunov stability theorem. At the end of the paper, numerical simulation is presented to illustrate the effectiveness of the results obtained in this paper.
- Published
- 2017
14. Existence and global asymptotic stability of positive almost periodic solution for a predator-prey system in an artificial lake
- Author
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Ali Moussaoui, E.H. Ait Dads, and M.A. Menouer
- Subjects
Lyapunov function ,Degree (graph theory) ,General Mathematics ,Applied Mathematics ,Mathematical analysis ,General Physics and Astronomy ,Order (ring theory) ,020206 networking & telecommunications ,Statistical and Nonlinear Physics ,02 engineering and technology ,01 natural sciences ,Stability (probability) ,Coincidence ,010305 fluids & plasmas ,symbols.namesake ,Exponential stability ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,symbols ,Uniqueness ,Special case ,Mathematics - Abstract
A periodic predator-prey model has been introduced in [5] to study the effect of water level on persistence or extinction of fish populations living in an artificial lake. By using the continuation theorem of Mawhin’s coincidence degree theory, the authors give sufficient conditions for the existence of at least one positive periodic solution. In this paper we study the problem in the general case. We begin by analyzing the invariance, permanence, non-persistence and the globally asymptotic stability for the system. Most interestingly, under additional conditions, we find that the periodic solution obtained in [5] is unique. Finally, in order to make the model system more realistic, we consider the special case when the periodicity in [5] is replaced by almost periodicity. We obtain conditions for existence, uniqueness and stability of a positive almost periodic solution. The methods used in this paper will be comparison theorems and Lyapunov functions. An example is employed to illustrate our result.
- Published
- 2017
15. Partial orders on conjugacy classes in the Weyl group and on unipotent conjugacy classes
- Author
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Jeffrey Adams, Xuhua He, and Sian Nie
- Subjects
Weyl group ,Pure mathematics ,Series (mathematics) ,General Mathematics ,010102 general mathematics ,Unipotent ,Reductive group ,01 natural sciences ,Injective function ,Primary: 20G07, Secondary: 06A07, 20F55, 20E45 ,symbols.namesake ,Conjugacy class ,0103 physical sciences ,FOS: Mathematics ,symbols ,Order (group theory) ,010307 mathematical physics ,Representation Theory (math.RT) ,0101 mathematics ,Algebraically closed field ,Mathematics::Representation Theory ,Mathematics - Representation Theory ,Mathematics - Abstract
Let $G$ be a reductive group over an algebraically closed field and let $W$ be its Weyl group. In a series of papers, Lusztig introduced a map from the set $[W]$ of conjugacy classes of $W$ to the set $[G_u]$ of unipotent classes of $G$. This map, when restricted to the set of elliptic conjugacy classes $[W_e]$ of $W$, is injective. In this paper, we show that Lusztig's map $[W_e] \to [G_u]$ is order-reversing, with respect to the natural partial order on $[W_e]$ arising from combinatorics and the natural partial order on $[G_u]$ arising from geometry., Comment: 25 pages
- Published
- 2021
16. New insights into the extended Malkus-Robbins dynamo
- Author
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Xitong Chen, Jianghong Bao, and Huanyu Yu
- Subjects
Riemann curvature tensor ,General Mathematics ,Applied Mathematics ,General Physics and Astronomy ,Statistical and Nonlinear Physics ,01 natural sciences ,Stability (probability) ,010305 fluids & plasmas ,symbols.namesake ,Bifurcation theory ,Differential geometry ,0103 physical sciences ,symbols ,Trajectory ,Applied mathematics ,010301 acoustics ,Bifurcation ,Eigenvalues and eigenvectors ,Mathematics ,Dynamo - Abstract
The present work is devoted to giving new insights into the extended Malkus-Robbins (EMR) dynamo. Firstly, based on differential geometry method, i.e. Kosambi-Cartan-Chern (KCC) theory, the paper investigates the Jacobi stability of the equilibrium and periodic orbit by the eigenvalues of the deviation curvature tensor. The deviation vector is applied to analyze the trajectory behaviors near the equilibrium and periodic orbit. Secondly, the zero-zero-Hopf bifurcation is investigated. The paper obtains the conditions that two periodic solutions appear at the bifurcation point and discusses their stability. Finally, on the global dynamics, the ultimate bound sets of the system are estimated. Numerical simulations are given to verify and visualize the corresponding theoretical results.
- Published
- 2021
17. Chaotic systems with asymmetric heavy-tailed noise: Application to 3D attractors
- Author
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Javier E. Contreras-Reyes
- Subjects
General Mathematics ,Applied Mathematics ,media_common.quotation_subject ,Gaussian ,Chaotic ,Skew ,General Physics and Astronomy ,Statistical and Nonlinear Physics ,Scale (descriptive set theory) ,01 natural sciences ,Asymmetry ,010305 fluids & plasmas ,Nonlinear Sciences::Chaotic Dynamics ,Noise ,symbols.namesake ,Skewness ,0103 physical sciences ,Attractor ,symbols ,Statistical physics ,010301 acoustics ,media_common ,Mathematics - Abstract
Yilmaz et al. (Fluct. Noise Lett. 17, 1830002, 2018) investigated the stochastic phenomenological bifurcations of a generalized Chua circuit driven by Skew-Gaussian distributed noise. They proved it is possible to decrease the number of scrolls by properly choosing the stochastic excitation, manipulating the skewness and noise intensity parameters. Based on the latter, this paper proposes an extension of skew-gaussian noise based on the family of Scale Mixtures of Skew-normal (SMSN) distributions, which includes the skew- t , the skew-gaussian, and the gaussian noises as particular cases. The Lorenz, Generalized Lorenz, Proto–Lorenzand Rossler attractors driven by skew- t distributed noise are considered. Results show that the chaotic regime’s behavior is influenced by the freedom parameter degrees of skew- t noise, increasing the noise variance. This paper concludes that noise intensity increases by rescaling the skew- t distribution at zero mean, rather than by increasing the asymmetry parameter.
- Published
- 2021
18. An enhanced multi-wing fractional-order chaotic system with coexisting attractors and switching hybrid synchronisation with its nonautonomous counterpart
- Author
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Binoy Krishna Roy and Manashita Borah
- Subjects
Wing ,General Mathematics ,Applied Mathematics ,media_common.quotation_subject ,Bandwidth (signal processing) ,Chaotic ,General Physics and Astronomy ,Statistical and Nonlinear Physics ,Lyapunov exponent ,Topology ,01 natural sciences ,Asymmetry ,010305 fluids & plasmas ,Nonlinear Sciences::Chaotic Dynamics ,Fractional dynamics ,symbols.namesake ,Control theory ,0103 physical sciences ,Attractor ,symbols ,Periodic orbits ,010301 acoustics ,Mathematics ,media_common - Abstract
This paper presents a new chaotic system that exhibits a two wing (2W) chaotic attractor in its integer order dynamics, three-wing (3W) and four-wing (4W) chaotic attractors in its fractional-order (FO) dynamics, and an eight-wing (8W) attractor in its nonautonomous fractional dynamics. An interesting feature of the proposed system is that two distinct periodic orbits coexist with a strange attractor that gradually evolves into a 4W attractor. The asymmetry, dissimilarity and topological structure of this proposed system with respect to those available in literature, manifest increased irregularity, which in turn indicate more chaos. Besides, the authors have drawn its comparison with various well-known fractional-order chaotic systems (FOCS)s to prove its enhanced features in terms of higher Lyapunov Exponent, fractional order orbital velocities, bandwidth, density, range of dynamical behaviour, etc. A control scheme is proposed to enable switching hybrid synchronisation between the 8W nonautonomous FOCS and the 4W autonomous FOCS, using the former as master and the latter as slave. This work throws light on the potential practical applicability of the proposed system by designing a circuit using minimum circuit components possible, thus signifying the objectives of the paper are finally achieved.
- Published
- 2017
19. Ill-posedness of the Prandtl equations in Sobolev spaces around a shear flow with general decay
- Author
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Cheng-Jie Liu and Tong Yang
- Subjects
Applied Mathematics ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,Prandtl number ,Mathematics::Analysis of PDEs ,01 natural sciences ,Physics::Fluid Dynamics ,010101 applied mathematics ,Sobolev space ,symbols.namesake ,Inviscid flow ,symbols ,0101 mathematics ,Exponential decay ,Shear flow ,Approximate solution ,Ill posedness ,Mathematics ,Variable (mathematics) - Abstract
Motivated by the paper Gerard-Varet and Dormy (2010) [6] [JAMS, 2010] about the linear ill-posedness for the Prandtl equations around a shear flow with exponential decay in normal variable, and the recent study of well-posedness on the Prandtl equations in Sobolev spaces, this paper aims to extend the result in [6] to the case when the shear flow has general decay. The key observation is to construct an approximate solution that captures the initial layer to the linearized problem motivated by the precise formulation of solutions to the inviscid Prandtl equations.
- Published
- 2017
20. On the global existence of smooth solutions to the multi-dimensional compressible euler equations with time-depending damping in half space
- Author
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Fei Hou
- Subjects
Cauchy problem ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,Structure (category theory) ,General Physics and Astronomy ,Boundary (topology) ,Half-space ,Vorticity ,01 natural sciences ,Euler equations ,010101 applied mathematics ,symbols.namesake ,Compressibility ,symbols ,Initial value problem ,0101 mathematics ,Mathematics - Abstract
This paper is a continue work of [4,5]. In the previous two papers, we studied the Cauchy problem of the multi-dimensional compressible Euler equations with time-depending damping term - μ ( 1 + t ) λ ρ u , where λ≥0 and μ > 0 are constants. We have showed that, for all λ≥0 and μ>0, the smooth solution to the Cauchy problem exists globally or blows up in finite time. In the present paper, instead of the Cauchy problem we consider the initial-boundary value problem in the half space ℝ d + with space dimension d = 2,3. With the help of the special structure of the equations and the fluid vorticity, we overcome the difficulty arisen from the boundary effect. We prove that there exists a global smooth solution for 0 ≤ λ
- Published
- 2017
21. Hamilton–Jacobi theory, symmetries and coisotropic reduction
- Author
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Manuel de León, David Martín de Diego, and Miguel Vaquero
- Subjects
Approximations of π ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,01 natural sciences ,Hamilton–Jacobi equation ,Hamiltonian system ,Algebra ,symbols.namesake ,Reduction procedure ,0103 physical sciences ,Homogeneous space ,symbols ,010307 mathematical physics ,0101 mathematics ,Hamiltonian (quantum mechanics) ,Symplectic geometry ,Mathematics - Abstract
Reduction theory has played a major role in the study of Hamiltonian systems. Whilst the Hamilton–Jacobi theory is one of the main tools to integrate the dynamics of certain Hamiltonian problems and a topic of research on its own. Moreover, the construction of several symplectic integrators relies on approximations of a complete solution of the Hamilton–Jacobi equation. The natural question that we address in this paper is how these two topics (reduction and Hamilton–Jacobi theory) fit together. We obtain a reduction and reconstruction procedure for the Hamilton–Jacobi equation with symmetries, even in a generalized sense to be clarified below. Several applications and relations to other reduction of the Hamilton–Jacobi theory are shown in the last section of the paper. It is remarkable that as by-product we obtain a generalization of the Ge–Marsden reduction procedure [18] and the results in [17] . Quite surprisingly, the classical ansatze available in the literature to solve the Hamilton–Jacobi equation (see [2] , [19] ) are also particular instances of our framework.
- Published
- 2017
22. A two-dimensional glimm type scheme on cauchy problem of two-dimensional scalar conservation law
- Author
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Xiaozhou Yang and Hui Kan
- Subjects
Cauchy problem ,Conservation law ,Pure mathematics ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,General Physics and Astronomy ,Type scheme ,01 natural sciences ,010101 applied mathematics ,Riemann hypothesis ,symbols.namesake ,symbols ,Entropy (information theory) ,Uniqueness ,0101 mathematics ,Mathematics - Abstract
In this paper, we construct a new two-dimensional convergent scheme to solve Cauchy problem of following two-dimensional scalar conservation law { ∂ t u + ∂ x f ( u ) + ∂ y g ( u ) = 0 , u ( x , y , 0 ) = u 0 ( x , y ) . In which initial data can be unbounded. Although the existence and uniqueness of the weak entropy solution are obtained, little is known about how to investigate two-dimensional or higher dimensional conservation law by the schemes based on wave interaction of 2D Riemann solutions and their estimation. So we construct such scheme in our paper and get some new results.
- Published
- 2017
23. New pathways and connections in number theory and analysis motivated by two incorrect claims of Ramanujan
- Author
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Arindam Roy, Atul Dixit, Bruce C. Berndt, and Alexandru Zaharescu
- Subjects
Discrete mathematics ,Series (mathematics) ,General Mathematics ,010102 general mathematics ,Divisor function ,Divisor (algebraic geometry) ,Divergent series ,01 natural sciences ,Ramanujan's sum ,010101 applied mathematics ,symbols.namesake ,Identity (mathematics) ,Number theory ,symbols ,0101 mathematics ,Convergent series ,Mathematics - Abstract
The focus of this paper commences with an examination of three (not obviously related) pages in Ramanujan's lost notebook, pages 336, 335, and 332, in decreasing order of attention. On page 336, Ramanujan proposes two identities, but the formulas are wrong – each is vitiated by divergent series. We concentrate on only one of the two incorrect “identities,” which may have been devised to attack the extended divisor problem. We prove here a corrected version of Ramanujan's claim, which contains the convergent series appearing in it. The convergent series in Ramanujan's faulty claim is similar to one used by G.F. Voronoi, G.H. Hardy, and others in their study of the classical Dirichlet divisor problem. This now brings us to page 335, which comprises two formulas featuring doubly infinite series of Bessel functions, the first being conjoined with the classical circle problem initiated by Gauss, and the second being associated with the Dirichlet divisor problem. The first and fourth authors, along with Sun Kim, have written several papers providing proofs of these two difficult formulas in different interpretations. In this monograph, we return to these two formulas and examine them in more general settings. The aforementioned convergent series in Ramanujan's “identity” is also similar to one that appears in a curious identity found in Chapter 15 in Ramanujan's second notebook, written in a more elegant, equivalent formulation on page 332 in the lost notebook. This formula may be regarded as a formula for ζ ( 1 2 ) , and in 1925, S. Wigert obtained a generalization giving a formula for ζ ( 1 k ) for any even integer k ≥ 2 . We extend the work of Ramanujan and Wigert in this paper. The Voronoi summation formula appears prominently in our study. In particular, we generalize work of J.R. Wilton and derive an analogue involving the sum of divisors function σ s ( n ) . The modified Bessel functions K s ( x ) arise in several contexts, as do Lommel functions. We establish here new series and integral identities involving modified Bessel functions and modified Lommel functions. Among other results, we establish a modular transformation for an infinite series involving σ s ( n ) and modified Lommel functions. We also discuss certain obscure related work of N.S. Koshliakov. We define and discuss two new related classes of integral transforms, which we call Koshliakov transforms, because he first found elegant special cases of each.
- Published
- 2017
24. Induced actions of B-Volterra operators on regular bounded martingale spaces
- Author
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Nazife Erkurşun-Özcan and Niyazi Anıl Gezer
- Subjects
Pure mathematics ,Volterra operator ,General Mathematics ,Boolean algebra (structure) ,010102 general mathematics ,010103 numerical & computational mathematics ,Shift operator ,01 natural sciences ,Projection (linear algebra) ,symbols.namesake ,Operator (computer programming) ,Norm (mathematics) ,Bounded function ,Filtration (mathematics) ,symbols ,0101 mathematics ,Mathematics - Abstract
A positive operator T : E → E on a Banach lattice E with an order continuous norm is said to be B -Volterra with respect to a Boolean algebra B of order projections of E if the bands canonically corresponding to elements of B are left fixed by T . A linearly ordered sequence ξ in B connecting 0 to 1 is called a forward filtration. A forward filtration can be used to lift the action of the B -Volterra operator T from the underlying Banach lattice E to an action of a new norm continuous operator T ˆ ξ : M r ( ξ ) → M r ( ξ ) on the Banach lattice M r ( ξ ) of regular bounded martingales on E corresponding to ξ . In the present paper, we study properties of these actions. The set of forward filtrations are left fixed by a function which erases the first order projection of a forward filtration and which shifts the remaining order projections towards 0. This function canonically induces a norm continuous shift operator s between two Banach lattices of regular bounded martingales. Moreover, the operators T ˆ ξ and s commute. Utilizing this fact with inductive limits, we construct a categorical limit space M T , ξ which is called the associated space of the pair ( T , ξ ) . We present new connections between theories of Boolean algebras, abstract martingales and Banach lattices.
- Published
- 2021
25. Geometry of slow–fast Hamiltonian systems and Painlevé equations
- Author
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E. I. Yakovlev and L. M. Lerman
- Subjects
General Mathematics ,010102 general mathematics ,Submanifold ,01 natural sciences ,Manifold ,Hamiltonian system ,010101 applied mathematics ,symbols.namesake ,Slow manifold ,Tangent space ,symbols ,0101 mathematics ,Hamiltonian (quantum mechanics) ,Mathematics::Symplectic Geometry ,Symplectic manifold ,Mathematical physics ,Mathematics ,Symplectic geometry - Abstract
In the first part of the paper we introduce some geometric tools needed to describe slow–fast Hamiltonian systems on smooth manifolds. We start with a smooth bundle p : M → B where ( M , ω ) is a C ∞ -smooth presymplectic manifold with a closed constant rank 2-form ω and ( B , λ ) is a smooth symplectic manifold. The 2-form ω is supposed to be compatible with the structure of the bundle, that is the bundle fibers are symplectic manifolds with respect to the 2-form ω and the distribution on M generated by kernels of ω is transverse to the tangent spaces of the leaves and the dimensions of the kernels and of the leaves are supplementary. This allows one to define a symplectic structure Ω e = ω + e − 1 p ∗ λ on M for any positive small e , where p ∗ λ is the lift of the 2-form λ to M . Given a smooth Hamiltonian H on M one gets a slow–fast Hamiltonian system with respect to Ω e . We define a slow manifold S M for this system. Assuming S M is a smooth submanifold, we define a slow Hamiltonian flow on S M . The second part of the paper deals with singularities of the restriction of p to S M . We show that if dim M = 4 , dim B = 2 and Hamilton function H is generic, then the behavior of the system near a singularity of fold type is described, to the main order, by the equation Painleve-I, and if this singularity is a cusp, then the related equation is Painleve-II.
- Published
- 2016
26. The nature of Lyapunov exponents is (+, +, −, −). Is it a hyperchaotic system?
- Author
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Jay Prakash Singh and Binoy Krishna Roy
- Subjects
Pure mathematics ,Mathematics::Dynamical Systems ,General Mathematics ,Applied Mathematics ,Mathematical analysis ,General Physics and Astronomy ,Statistical and Nonlinear Physics ,Lyapunov exponent ,01 natural sciences ,010305 fluids & plasmas ,Nonlinear Sciences::Chaotic Dynamics ,Quantitative measure ,symbols.namesake ,Computer Science::Systems and Control ,0103 physical sciences ,symbols ,010301 acoustics ,Mathematics ,Sign (mathematics) - Abstract
This review paper aims at answering a basic question on the sign of Lyapunov exponents. A few recent papers reported hyperchaotic system having the sign of Lyapunov exponents as (+, +, −, −). Such (+, +, −, −) sign of Lyapunov exponents is in contradiction with the well known (+, +, 0, −) sign of Lyapunov exponents for a 4-D hyperchaotic system. This paper thus discusses various issues related to Lyapunov exponents and proves that the reported sign of (+, +, −, −) Lyapunov exponents is actually (+, +, 0, −) or (+, 0, −, −). This clarification is very important and essential since Lyapunov exponents are the only quantitative measure for the existence of hyperchaos. Three different algorithms are used for calculating the Laypunov exponents to prove the actual sign of Lyapunov exponents for a hyperchaotic system.
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- 2016
27. Bergman kernels on punctured Riemann surfaces
- Author
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Xiaonan Ma, George Marinescu, and Hugues Auvray
- Subjects
Mathematics - Differential Geometry ,Mathematics(all) ,Pure mathematics ,General Mathematics ,Poincaré metric ,Holomorphic function ,01 natural sciences ,symbols.namesake ,Uniform norm ,Line bundle ,0103 physical sciences ,FOS: Mathematics ,Hermitian manifold ,Number Theory (math.NT) ,Tensor ,Complex Variables (math.CV) ,0101 mathematics ,Mathematics ,Bergman kernel ,Mathematics - Number Theory ,Mathematics - Complex Variables ,Mathematics::Complex Variables ,Riemann surface ,010102 general mathematics ,General Medicine ,16. Peace & justice ,Differential Geometry (math.DG) ,Metric (mathematics) ,symbols ,010307 mathematical physics - Abstract
In this paper we consider a punctured Riemann surface endowed with a Hermitian metric which equals the Poincar\'e metric near the punctures and a holomorphic line bundle which polarizes the metric. We show that the Bergman kernel can be localized around the singularities and its local model is the Bergman kernel of the punctured unit disc endowed with the standard Poincar\'e metric. As a consequence, we obtain an optimal uniform estimate of the supremum norm of the Bergman kernel, involving a fractional growth order of the tensor power., Comment: 42 pages, 2 figures; v.2 is a final update to agree with the published paper
- Published
- 2016
28. Complex dynamics of an eco-epidemiological model with different competition coefficients and weak Allee in the predator
- Author
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Joydev Chattopadhyay, Md. Saifuddin, Sudip Samanta, Santanu Biswas, and Susmita Sarkar
- Subjects
Equilibrium point ,Hopf bifurcation ,education.field_of_study ,General Mathematics ,Applied Mathematics ,Population ,Chaotic ,General Physics and Astronomy ,Statistical and Nonlinear Physics ,Lyapunov exponent ,01 natural sciences ,010101 applied mathematics ,symbols.namesake ,Complex dynamics ,Control theory ,0103 physical sciences ,symbols ,Quantitative Biology::Populations and Evolution ,Carrying capacity ,Statistical physics ,0101 mathematics ,education ,010301 acoustics ,Mathematics ,Allee effect - Abstract
The paper explores an eco-epidemiological model with weak Allee in predator, and the disease in the prey population. We consider a predator-prey model with type II functional response. The curiosity of this paper is to consider different competition coefficients within the prey population, which leads to the emergent carrying capacity. We perform the local and global stability analysis of the equilibrium points and the Hopf bifurcation analysis around the endemic equilibrium point. Further we pay attention to the chaotic dynamics which is produced by disease. Our numerical simulations reveal that the three species eco-epidemiological system without weak-Allee induced chaos from stable focus for increasing the force of infection, whereas in the presence of the weak-Allee effect, it exhibits stable solution. We conclude that chaotic dynamics can be controlled by the Allee parameter as well as the competition coefficients. We apply basic tools of non-linear dynamics such as Poincare section and maximum Lyapunov exponent to identify chaotic behavior of the system.
- Published
- 2016
29. Comment for 'Existence and Hyers-Ulam stability for a nonlinear singular fractional differential equations with Mittag-Leffler kernel'
- Author
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Xiaoyan Li
- Subjects
General Mathematics ,Applied Mathematics ,General Physics and Astronomy ,Statistical and Nonlinear Physics ,Function (mathematics) ,Expression (computer science) ,01 natural sciences ,Stability (probability) ,010305 fluids & plasmas ,Nonlinear system ,symbols.namesake ,Fractal ,Green's function ,Kernel (statistics) ,0103 physical sciences ,symbols ,Applied mathematics ,Fractional differential ,010301 acoustics ,Mathematics - Abstract
In a published paper of Journal of Chaos, Solitons and Fractals, some miss prints were found. One is about the calculation of the solution and also about the expression of the solution using Green’s function of the fractional differential equation studied in this paper; The others are for the properties for Green’s function, these miss prints affected the deriving of the main results in Khan’s paper, some corrections for Khan’s paper should be needed. In this paper, we make some corrections and give the correct proof proceeding for the results, a new example is given to validate part of the proven results.
- Published
- 2021
30. Pulsating waves in a dissipative medium with Delta sources on a periodic lattice
- Author
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Je Chiang Tsai, Xinfu Chen, and Xing Liang
- Subjects
Bistability ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,Continuum (design consultancy) ,Dirac delta function ,01 natural sciences ,010101 applied mathematics ,symbols.namesake ,Classical mechanics ,Exponential stability ,symbols ,Dissipative system ,Heat equation ,Uniqueness ,0101 mathematics ,Focus (optics) ,Mathematics - Abstract
This paper studies a dissipative heat equation with Delta sources of non-linear strength located on a periodic lattice. The model arises from intracellular waves in continuum excitable media with discrete release sites. Due to the presence of Delta sources, the solution of the model has discontinuous spatial derivatives. We focus on the bistable regime of the model, determined by the decay strength parameter a and the separation distance L between release sites, in which the model admits exactly three L-periodic steady states. We establish the existence of pulsating waves spatially connecting them. For the case of waves connecting two stable L-periodic steady states, the uniqueness and global exponential stability of pulsating waves are shown. Also a new technique is introduced to find the fine structure of the tails of pulsating waves.
- Published
- 2021
31. Global well-posedness and scattering for the Dysthe equation in L2(R2)
- Author
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Jean-Claude Saut, Razvan Mosincat, and Didier Pilod
- Subjects
Small data ,Scattering ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,Bilinear interpolation ,01 natural sciences ,010305 fluids & plasmas ,symbols.namesake ,Fourier transform ,Norm (mathematics) ,0103 physical sciences ,Bounded variation ,symbols ,Flow map ,0101 mathematics ,Schrödinger's cat ,Mathematics - Abstract
This paper focuses on the Dysthe equation which is a higher order approximation of the water waves system in the modulation (Schrodinger) regime and in the infinite depth case. We first review the derivation of the Dysthe and related equations. Then we study the initial-value problem. We prove a small data global well-posedness and scattering result in the critical space L 2 ( R 2 ) . This result is sharp in view of the fact that the flow map cannot be C 3 continuous below L 2 ( R 2 ) . Our analysis relies on linear and bilinear Strichartz estimates in the context of the Fourier restriction norm method. Moreover, since we are at a critical level, we need to work in the framework of the atomic space U S 2 and its dual V S 2 of square bounded variation functions. We also prove that the initial-value problem is locally well-posed in H s ( R 2 ) , s > 0 . Our results extend to the finite depth version of the Dysthe equation.
- Published
- 2021
32. Exponential tractability of linear weighted tensor product problems in the worst-case setting for arbitrary linear functionals
- Author
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Peter Kritzer, Henryk Woźniakowski, and Friedrich Pillichshammer
- Subjects
Statistics and Probability ,Discrete mathematics ,Numerical Analysis ,Polynomial ,Control and Optimization ,Algebra and Number Theory ,Logarithm ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,Hilbert space ,010103 numerical & computational mathematics ,01 natural sciences ,Exponential polynomial ,Exponential function ,Singular value ,symbols.namesake ,Tensor product ,Bounded function ,symbols ,0101 mathematics ,Mathematics - Abstract
We study the approximation of compact linear operators defined over certain weighted tensor product Hilbert spaces. The information complexity is defined as the minimal number of arbitrary linear functionals needed to obtain an e -approximation for the d -variate problem which is fully determined in terms of the weights and univariate singular values. Exponential tractability means that the information complexity is bounded by a certain function that depends polynomially on d and logarithmically on e − 1 . The corresponding unweighted problem was studied in Hickernell et al. (2020) with many negative results for exponential tractability. The product weights studied in the present paper change the situation. Depending on the form of polynomial dependence on d and logarithmic dependence on e − 1 , we study exponential strong polynomial, exponential polynomial, exponential quasi-polynomial, and exponential ( s , t ) -weak tractability with max ( s , t ) ≥ 1 . For all these notions of exponential tractability, we establish necessary and sufficient conditions on weights and univariate singular values for which it is indeed possible to achieve the corresponding notion of exponential tractability. The case of exponential ( s , t ) -weak tractability with max ( s , t ) 1 is left for future study. The paper uses some general results obtained in Hickernell et al. (2020) and Kritzer and Woźniakowski (2019).
- Published
- 2020
33. Analysis of fractional fishery model with reserve area in the context of time-fractional order derivative
- Author
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Fulgence Mansal and Ndolane Sene
- Subjects
Equilibrium point ,Lyapunov function ,Discretization ,General Mathematics ,Applied Mathematics ,General Physics and Astronomy ,Statistical and Nonlinear Physics ,Context (language use) ,01 natural sciences ,010305 fluids & plasmas ,Fractional calculus ,Fishery ,symbols.namesake ,Exponential stability ,0103 physical sciences ,Jacobian matrix and determinant ,symbols ,Quantitative Biology::Populations and Evolution ,Uniqueness ,010301 acoustics ,Mathematics - Abstract
The paper addresses the mathematical analysis of the fishery model in the context of the fractional derivative operator. We use the Caputo–Fabrizio derivative in the investigations. We first prove the fishery model is biologically well definite by proposing the existence and the uniqueness of its solution. The main objective of this paper is to study the dynamics of the predator and the prey in the fishery model when the fractional-order derivative is used. Notably, we analyze the impact of the fractional-order derivative on the dynamics of the fishery model explicitly. To answer this issue, we introduce a new numerical scheme based on the discretization of the fractional integral associated with the Caputo–Fabrizio derivative. The numerical simulations of the solutions of the fractional model are intended to illustrate the numerical scheme presented in our paper. We finish by analyzing the local and global asymptotic stability of the equilibrium points using the Jacobian matrix and the Lyapunov direct method. The Lyapunov function is constructed using standard construction. We notice here that the solutions of the fractional fishery model with different values of the orders describes a cycle when we depict them in three dimensional spaces in time, and furthermore the marine reserves ensure the sustainability of fractional system.
- Published
- 2020
34. Optimal convergence rate of the vanishing shear viscosity limit for compressible Navier-Stokes equations with cylindrical symmetry
- Author
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Xinhua Zhao, Huanyao Wen, Tong Yang, and Changjiang Zhu
- Subjects
Applied Mathematics ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,Prandtl number ,Boundary (topology) ,01 natural sciences ,Symmetry (physics) ,Physics::Fluid Dynamics ,010101 applied mathematics ,Boundary layer ,symbols.namesake ,Rate of convergence ,symbols ,Compressibility ,Limit (mathematics) ,Boundary value problem ,0101 mathematics ,Mathematics - Abstract
We consider the initial boundary value problem for the isentropic compressible Navier-Stokes equations with cylindrical symmetry. The existence of boundary layers is well-known when the shear viscosity vanishes. In this paper, we derive explicit Prandtl type boundary layer equations and prove the global in time stability of the boundary layer profile together with the optimal convergence rate of the vanishing shear viscosity limit without any smallness assumption on the initial and boundary data.
- Published
- 2021
35. Instability of high dimensional Hamiltonian systems: Multiple resonances do not impede diffusion
- Author
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Amadeu Delshams, Rafael de la Llave, Tere M. Seara, Universitat Politècnica de Catalunya. Departament de Matemàtiques, and Universitat Politècnica de Catalunya. SD - Sistemes Dinàmics de la UPC
- Subjects
Pure mathematics ,Mathematics(all) ,General Mathematics ,Dynamical Systems (math.DS) ,Scattering map ,01 natural sciences ,010305 fluids & plasmas ,Hamiltonian system ,symbols.namesake ,Arnold diffusion ,0103 physical sciences ,FOS: Mathematics ,Sistemes hamiltonians ,Mathematics - Dynamical Systems ,Hamiltonian systems ,0101 mathematics ,Mathematics ,Scattering ,010102 general mathematics ,Mathematical analysis ,Instability ,Matemàtiques i estadística [Àrees temàtiques de la UPC] ,Resonance ,Torus ,Codimension ,37J40 ,Hamiltonian ,Resonances ,symbols ,Hamiltonian (quantum mechanics) ,Symplectic geometry - Abstract
We consider models given by Hamiltonians of the form H ( I , φ , p , q , t ; e ) = h ( I ) + ∑ j = 1 n ± ( 1 2 p j 2 + V j ( q j ) ) + e Q ( I , φ , p , q , t ; e ) where I ∈ I ⊂ R d , φ ∈ T d , p , q ∈ R n , t ∈ T 1 . These are higher dimensional analogues, both in the center and hyperbolic directions, of the models studied in [28] , [29] , [43] and are usually called “a-priori unstable Hamiltonian systems”. All these models present the large gap problem. We show that, for 0 e ≪ 1 , under regularity and explicit non-degeneracy conditions on the model, there are orbits whose action variables I perform rather arbitrary excursions in a domain of size O ( 1 ) . This domain includes resonance lines and, hence, large gaps among d-dimensional KAM tori. This phenomenon is known as Arnold diffusion. The method of proof follows closely the strategy of [28] , [29] . The main new phenomenon that appears when the dimension d of the center directions is larger than one is the existence of multiple resonances in the space of actions I ∈ I ⊂ R d . We show that, since these multiple resonances happen in sets of codimension greater than one in the space of actions I, they can be contoured. This corresponds to the mechanism called diffusion across resonances in the Physics literature. The present paper, however, differs substantially from [28] , [29] . On the technical details of the proofs, we have taken advantage of the theory of the scattering map developed in [31] —notably the symplectic properties—which were not available when the above papers were written. We have analyzed the conditions imposed on the resonances in more detail. More precisely, we have found that there is a simple condition on the Melnikov potential which allows us to conclude that the resonances are crossed. In particular, this condition does not depend on the resonances. So that the results are new even when applied to the models in [28] , [29] .
- Published
- 2016
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36. On the strong divergence of Hilbert transform approximations and a problem of Ul’yanov
- Author
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Holger Boche and Volker Pohl
- Subjects
Numerical Analysis ,Sequence ,Conjecture ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,020206 networking & telecommunications ,02 engineering and technology ,01 natural sciences ,Combinatorics ,symbols.namesake ,Uniform norm ,Subsequence ,0202 electrical engineering, electronic engineering, information engineering ,symbols ,Hilbert transform ,0101 mathematics ,Divergence (statistics) ,Finite set ,Fourier series ,Analysis ,Mathematics - Abstract
This paper studies the approximation of the Hilbert transform f ? = H f of continuous functions f with continuous conjugate f ? based on a finite number of samples. It is known that every sequence { H N f } N ? N which approximates f ? from samples of f diverges (weakly) with respect to the uniform norm. This paper conjectures that all of these approximation sequences even contain no convergent subsequence. A property which is termed strong divergence.The conjecture is supported by two results. First it is proven that the sequence of the sampled conjugate Fejer means diverges strongly. Second, it is shown that for every sample based approximation method { H N } N ? N there are functions f such that ? H N f ? ∞ exceeds any given bound for any given number of consecutive indices N .As an application, the later result is used to investigate a problem associated with a question of Ul'yanov on Fourier series which is related to the possibility to construct adaptive approximation methods to determine the Hilbert transform from sampled data. This paper shows that no such approximation method with a finite search horizon exists.
- Published
- 2016
37. Bifurcation and multiplicity results for critical nonlocal fractional Laplacian problems
- Author
-
Raffaella Servadei, Giovanni Molica Bisci, Alessio Fiscella, Fiscella, A, Molica Bisci, G, and Servadei, R
- Subjects
Discrete mathematics ,Pure mathematics ,General Mathematics ,variational techniques ,010102 general mathematics ,Multiplicity (mathematics) ,integrodifferential operators ,01 natural sciences ,Dirichlet distribution ,Fractional Laplacian ,010101 applied mathematics ,Sobolev space ,symbols.namesake ,critical nonlinearities ,Operator (computer programming) ,Fractional Laplacian, critical nonlinearities, best fractional critical Sobolev constant, variational techniques, integrodifferential operators ,Bounded function ,best fractional critical Sobolev constant ,fractional Laplacian, critical nonlinearities, best fractional critical Sobolev constant, variational techniques, integrodifferential operators ,symbols ,Exponent ,0101 mathematics ,Bifurcation ,Eigenvalues and eigenvectors ,Mathematics - Abstract
In this paper we consider the following critical nonlocal problem { − L K u = λ u + | u | 2 ⁎ − 2 u in Ω u = 0 in R n ∖ Ω , where s ∈ ( 0 , 1 ) , Ω is an open bounded subset of R n , n > 2 s , with continuous boundary, λ is a positive real parameter, 2 ⁎ : = 2 n / ( n − 2 s ) is the fractional critical Sobolev exponent, while L K is the nonlocal integrodifferential operator L K u ( x ) : = ∫ R n ( u ( x + y ) + u ( x − y ) − 2 u ( x ) ) K ( y ) d y , x ∈ R n , whose model is given by the fractional Laplacian − ( − Δ ) s . Along the paper, we prove a multiplicity and bifurcation result for this problem, using a classical theorem in critical points theory. Precisely, we show that in a suitable left neighborhood of any eigenvalue of − L K (with Dirichlet boundary data) the number of nontrivial solutions for the problem under consideration is at least twice the multiplicity of the eigenvalue. Hence, we extend the result got by Cerami, Fortunato and Struwe in [14] for classical elliptic equations, to the case of nonlocal fractional operators.
- Published
- 2016
38. Binary generalized synchronization
- Author
-
Vladimir I. Ponomarenko, Alexander E. Hramov, Olga I. Moskalenko, Mikhail D. Prokhorov, and Alexey A. Koronovskii
- Subjects
Discrete mathematics ,Coupling strength ,Dynamical systems theory ,General Mathematics ,Applied Mathematics ,Synchronization of chaos ,General Physics and Astronomy ,Binary number ,Statistical and Nonlinear Physics ,Lyapunov exponent ,01 natural sciences ,010305 fluids & plasmas ,symbols.namesake ,Aperiodic graph ,Auxiliary system ,0103 physical sciences ,Synchronization (computer science) ,symbols ,Statistical physics ,010306 general physics ,Mathematics - Abstract
In this paper we report for the first time on the binary generalized synchronization, when for the certain values of the coupling strength two unidirectionally coupled dynamical systems generating the aperiodic binary sequences are in the generalized synchronization regime. The presence of the binary generalized synchronization has been revealed with the help of both the auxiliary system approach and the largest conditional Lyapunov exponent calculation. The mechanism resulting in the binary generalized synchronization has been explained. The finding discussed in this paper gives a strong potential for new applications under many relevant circumstances.
- Published
- 2016
39. Convergence rate of solutions to strong contact discontinuity for the one-dimensional compressible radiation hydrodynamics model
- Author
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Zhengzheng Chen, Wenjuan Wang, and Xiaojuan Chai
- Subjects
General Mathematics ,010102 general mathematics ,Mathematical analysis ,Zero (complex analysis) ,General Physics and Astronomy ,Euler system ,01 natural sciences ,010101 applied mathematics ,Discontinuity (linguistics) ,symbols.namesake ,Radiation flux ,Rate of convergence ,Boltzmann constant ,symbols ,Limit (mathematics) ,0101 mathematics ,Constant (mathematics) ,Mathematics - Abstract
This paper is concerned with a singular limit for the one-dimensional compressible radiation hydrodynamics model. The singular limit we consider corresponds to the physical problem of letting the Bouguer number infinite while keeping the Boltzmann number constant. In the case when the corresponding Euler system admits a contact discontinuity wave, Wang and Xie (2011) [12] recently verified this singular limit and proved that the solution of the compressible radiation hydrodynamics model converges to the strong contact discontinuity wave in the L∞-norm away from the discontinuity line at a rate of e 1 4 , as the reciprocal of the Bouguer number tends to zero. In this paper, Wang and Xie's convergence rate is improved to e 7 8 by introducing a new a priori assumption and some refined energy estimates. Moreover, it is shown that the radiation flux q tends to zero in the L∞-norm away from the discontinuity line, at a convergence rate as the reciprocal of the Bouguer number tends to zero.
- Published
- 2016
40. Turing-Hopf bifurcation in a diffusive mussel-algae model with time-fractional-order derivative
- Author
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Behzad Ghanbari, Soufiane Bentout, Salih Djilali, and Abdelheq Mezouaghi
- Subjects
Hopf bifurcation ,General Mathematics ,Applied Mathematics ,General Physics and Astronomy ,Order (ring theory) ,Pattern formation ,Statistical and Nonlinear Physics ,Derivative ,Codimension ,Type (model theory) ,01 natural sciences ,010305 fluids & plasmas ,symbols.namesake ,0103 physical sciences ,symbols ,Applied mathematics ,010301 acoustics ,Turing ,computer ,Bifurcation ,computer.programming_language ,Mathematics - Abstract
In this paper, we consider a time fractional-order derivative for a diffusive mussel–algae model. The existence of pattern formation was the subject of interest of many previous research works in the case of the diffusive mussel–algae model. Examples include the Turing instability, Hopf bifurcation, Turing-Hopf bifurcation, and others. The presence of the time–fractional–order derivative never been investigated in this model. Next to it ecological relevant, it can generate some important patterns. One of these patterns is produced by the presence of the Turing-Hopf bifurcation. Therefore, our main interest is to analyze the effect of the time fractional–order derivative on the spatiotemporal behavior of the solution, which never been achieved for the mussel-algae model. Besides, Turing–Hopf was studied exclusively on the classical reaction-diffusion systems, where it was also considered for the diffusive mussel-algae model. Thus, our paper puts the fist steps on proving the existence of this type of codimension bifurcation on the diffusive systems with time fractional–order–derivative systems. Further, a suitable numerical simulations are used for confirming the theoretical obtained results.
- Published
- 2020
41. Calculating the spectral factorization and outer functions by sampling-based approximations—Fundamental limitations
- Author
-
Volker Pohl and Holger Boche
- Subjects
Numerical Analysis ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,Sampling (statistics) ,Spectral density ,010103 numerical & computational mathematics ,Function (mathematics) ,Dirichlet's energy ,Spectral theorem ,Hardy space ,Singular integral ,01 natural sciences ,symbols.namesake ,symbols ,0101 mathematics ,Closed-form expression ,Analysis ,Mathematics - Abstract
This paper considers the problem of approximating the spectral factor of continuous spectral densities with finite Dirichlet energy based on finitely many samples of these spectral densities. Although there exists a closed form expression for the spectral factor, this formula shows a very complicated behavior because of the non-linear dependency of the spectral factor from spectral density and because of a singular integral in this expression. Therefore approximation methods are usually applied to calculate the spectral factor. It is shown that there exists no sampling-based method which depends continuously on the samples and which is able to approximate the spectral factor for all densities in this set. Instead, to any sampling-based approximation method there exists a large set of spectral densities so that the approximation method does not converge to the spectral factor for every spectral density in this set as the number of available sampling points is increased. The paper will also show that the same results hold for sampling-based algorithms for the calculation of the outer function in the theory of Hardy spaces.
- Published
- 2020
42. Existence and nonexistence of extremals for critical Adams inequalities in R4 and Trudinger-Moser inequalities in R2
- Author
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Guozhen Lu, Maochun Zhu, and Lu Chen
- Subjects
Pure mathematics ,Current (mathematics) ,Inequality ,General Mathematics ,media_common.quotation_subject ,010102 general mathematics ,Function (mathematics) ,Space (mathematics) ,01 natural sciences ,symbols.namesake ,Fourier transform ,0103 physical sciences ,Domain (ring theory) ,symbols ,Order (group theory) ,010307 mathematical physics ,0101 mathematics ,Symmetry (geometry) ,Mathematics ,media_common - Abstract
Though much progress has been made with respect to the existence of extremals of the critical first order Trudinger-Moser inequalities in W 1 , n ( R n ) and higher order Adams inequalities on finite domain Ω ⊂ R n , whether there exists an extremal function for the critical higher order Adams inequalities on the entire space R n still remains open. The current paper represents the first attempt in this direction by considering the critical second order Adams inequality in the entire space R 4 . The classical blow-up procedure cannot apply to solving the existence of critical Adams type inequality because of the absence of the Polya-Szego type inequality. In this paper, we develop some new ideas and approaches based on a sharp Fourier rearrangement principle (see [31] ), sharp constants of the higher-order Gagliardo-Nirenberg inequalities and optimal poly-harmonic truncations to study the existence and nonexistence of the maximizers for the Adams inequalities in R 4 of the form S ( α ) = sup ‖ u ‖ H 2 = 1 ∫ R 4 ( exp ( 32 π 2 | u | 2 ) − 1 − α | u | 2 ) d x , where α ∈ ( − ∞ , 32 π 2 ) . We establish the existence of the threshold α ⁎ , where α ⁎ ≥ ( 32 π 2 ) 2 B 2 2 and B 2 ≥ 1 24 π 2 , such that S ( α ) is attained if 32 π 2 − α α ⁎ , and is not attained if 32 π 2 − α > α ⁎ . This phenomenon has not been observed before even in the case of first order Trudinger-Moser inequality. Therefore, we also establish the existence and non-existence of an extremal function for the Trudinger-Moser inequality on R 2 . Furthermore, the symmetry of the extremal functions can also be deduced through the Fourier rearrangement principle.
- Published
- 2020
43. Truncated Hecke-Rogers type series
- Author
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Ae Ja Yee and Chun Wang
- Subjects
Pure mathematics ,Series (mathematics) ,Differential equation ,General Mathematics ,010102 general mathematics ,Type (model theory) ,Mathematical proof ,01 natural sciences ,symbols.namesake ,GEORGE (programming language) ,Pentagonal number theorem ,0103 physical sciences ,Euler's formula ,symbols ,010307 mathematical physics ,0101 mathematics ,Mathematics - Abstract
The recent work of George Andrews and Mircea Merca on the truncated version of Euler's pentagonal number theorem has opened up a new study on truncated theta series. Since then several papers on the topic have followed. The main purpose of this paper is to generalize the study to Hecke-Rogers type double series, which are associated with some interesting partition functions. Our proofs heavily rely on a formula from the work of Zhi-Guo Liu on the q-partial differential equations and q-series.
- Published
- 2020
44. Representations of mock theta functions
- Author
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Dandan Chen and Liuquan Wang
- Subjects
Pure mathematics ,Mathematics - Number Theory ,Series (mathematics) ,General Mathematics ,010102 general mathematics ,Parameterized complexity ,01 natural sciences ,Ramanujan theta function ,symbols.namesake ,Identity (mathematics) ,Mathematics - Classical Analysis and ODEs ,0103 physical sciences ,Classical Analysis and ODEs (math.CA) ,FOS: Mathematics ,symbols ,Mathematics - Combinatorics ,05A30, 11B65, 33D15, 11E25, 11F11, 11F27, 11P84 ,Number Theory (math.NT) ,Combinatorics (math.CO) ,010307 mathematical physics ,0101 mathematics ,Mathematics - Abstract
Motivated by the works of Liu, we provide a unified approach to find Appell-Lerch series and Hecke-type series representations for mock theta functions. We establish a number of parameterized identities with two parameters $a$ and $b$. Specializing the choices of $(a,b)$, we not only give various known and new representations for the mock theta functions of orders 2, 3, 5, 6 and 8, but also present many other interesting identities. We find that some mock theta functions of different orders are related to each other, in the sense that their representations can be deduced from the same $(a,b)$-parameterized identity. Furthermore, we introduce the concept of false Appell-Lerch series. We then express the Appell-Lerch series, false Appell-Lerch series and Hecke-type series in this paper using the building blocks $m(x,q,z)$ and $f_{a,b,c}(x,y,q)$ introduced by Hickerson and Mortenson, as well as $\overline{m}(x,q,z)$ and $\overline{f}_{a,b,c}(x,y,q)$ introduced in this paper. We also show the equivalences of our new representations for several mock theta functions and the known representations., Comment: 87 pages, comments are welcome. We have extended the previous version
- Published
- 2020
45. Positive vector solutions for nonlinear Schrödinger systems with strong interspecies attractive forces
- Author
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Jinmyoung Seok, Jaeyoung Byeon, and Ohsang Kwon
- Subjects
Condensed Matter::Quantum Gases ,Interaction forces ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,Structure (category theory) ,01 natural sciences ,010101 applied mathematics ,Nonlinear system ,symbols.namesake ,Classical mechanics ,symbols ,0101 mathematics ,Interspecies interaction ,Schrödinger's cat ,Mathematics - Abstract
In this paper we study the structure of positive vector solutions for nonlinear Schrodinger systems with 3 components when all interspecies interaction forces are positive and large while all intraspecies interaction forces are positive and fixed. We will show that the structure strongly depends on some relation of large interspecies interaction forces.
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- 2020
46. Ground states of nonlinear Schrödinger systems with mixed couplings
- Author
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Yuanze Wu and Juncheng Wei
- Subjects
Interaction forces ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,Block (permutation group theory) ,01 natural sciences ,Measure (mathematics) ,010101 applied mathematics ,Nonlinear system ,symbols.namesake ,symbols ,0101 mathematics ,Schrödinger's cat ,Mathematics ,Mathematical physics - Abstract
We consider the following k-coupled nonlinear Schrodinger systems: { − Δ u j + λ j u j = μ j u j 3 + ∑ i = 1 , i ≠ j k β i , j u i 2 u j in R N , u j > 0 in R N , u j ( x ) → 0 as | x | → + ∞ , j = 1 , 2 , ⋯ , k , where N ≤ 3 , k ≥ 3 , λ j , μ j > 0 are constants and β i , j = β j , i ≠ 0 are parameters. There have been intensive studies for the above systems when k = 2 or the systems are purely attractive ( β i , j > 0 , ∀ i ≠ j ) or purely repulsive ( β i , j 0 , ∀ i ≠ j ); however very few results are available for k ≥ 3 when the systems admit mixed couplings and the components are organized into groups, i.e., there exist ( i 1 , j 1 ) and ( i 2 , j 2 ) such that β i 1 , j 1 > 0 and β i 2 , j 2 0 . In this paper we give the first systematic and an (almost) complete study on the existence of ground states when the systems admit mixed couplings and the components are organized into groups. We first divide these systems into repulsive-mixed and total-mixed cases. In the first case we prove nonexistence of ground states. In the second case we give a necessary condition for the existence of ground states and also provide estimates for Morse index. The key idea is the block decomposition of the systems (optimal block decompositions, eventual block decompositions), and the measure of total interaction forces between different blocks. Finally the assumptions on the existence of ground states are shown to be optimal in some special cases.
- Published
- 2020
47. Lelong–Poincaré formula in symplectic and almost complex geometry
- Author
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Alexandre Sukhov and Emmanuel Mazzilli
- Subjects
Pure mathematics ,Almost complex manifold ,Mathematics::Complex Variables ,General Mathematics ,010102 general mathematics ,Vector bundle ,01 natural sciences ,General family ,symbols.namesake ,Mathematics::Algebraic Geometry ,Complex geometry ,Convergence (routing) ,Poincaré conjecture ,symbols ,Mathematics::Differential Geometry ,0101 mathematics ,Mathematics::Symplectic Geometry ,Symplectic geometry ,Mathematics - Abstract
In this paper, we present two applications of the theory of singular connections developed by Harvey and Lawson (1993). The first one is a version of the Lelong–Poincare formula with estimates for sections of vector bundles over an almost complex manifold. The second one is a convergence theorem for divisors associated to a general family of symplectic submanifolds constructed by Donaldson (1996) (the case of hypersurfaces) and by Auroux in (1997) (for arbitrary dimensional submanifolds).
- Published
- 2020
48. On the structure of variable exponent spaces
- Author
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Francisco L. Hernández, Mauro Sanchiz, César Ruiz, and Julio Flores
- Subjects
46E30, 47B60 ,Pure mathematics ,Variable exponent ,General Mathematics ,010102 general mathematics ,Structure (category theory) ,010103 numerical & computational mathematics ,Disjoint sets ,Cantor function ,01 natural sciences ,Functional Analysis (math.FA) ,Mathematics - Functional Analysis ,symbols.namesake ,Singularity ,Computer Science::Systems and Control ,FOS: Mathematics ,symbols ,0101 mathematics ,Mathematics - Abstract
The first part of this paper surveys several results on the lattice structure of variable exponent Lebesgue function spaces (or Nakano spaces) L p ( ⋅ ) ( Ω ) . In the second part strictly singular and disjointly strictly singular operators between spaces L p ( ⋅ ) ( Ω ) are studied. New results on the disjoint strict singularity of the inclusions L p ( ⋅ ) ( Ω ) ↪ L q ( ⋅ ) ( Ω ) are given.
- Published
- 2020
49. Long range scattering for the complex-valued Klein-Gordon equation with quadratic nonlinearity in two dimensions
- Author
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Kota Uriya, Jun Ichi Segata, and Satoshi Masaki
- Subjects
Logarithm ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,Gauge (firearms) ,35L71 ,01 natural sciences ,Term (time) ,010101 applied mathematics ,symbols.namesake ,Nonlinear system ,Range (mathematics) ,Mathematics - Analysis of PDEs ,FOS: Mathematics ,symbols ,0101 mathematics ,Invariant (mathematics) ,Constant (mathematics) ,Klein–Gordon equation ,Analysis of PDEs (math.AP) ,Mathematics - Abstract
In this paper, we study large time behavior of complex-valued solutions to nonlinear Klein-Gordon equation with a gauge invariant quadratic nonlinearity in two spatial dimensions. To find a possible asymptotic behavior, we consider the final value problem. It turns out that one possible behavior is a linear solution with a logarithmic phase correction as in the real-valued case. However, the shape of the logarithmic correction term has one more parameter which is also given by the final data. In the real case the parameter is constant so one cannot see its effect. However, in the complex case it varies in general. The one dimensional case is also discussed., Comment: 25 papges, 2 figures
- Published
- 2020
50. Hardy type inequalities and parametric Lamb equation
- Author
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R. G. Nasibullin and R. V. Makarov
- Subjects
Pure mathematics ,Euclidean space ,General Mathematics ,010102 general mathematics ,Open set ,Regular polygon ,Boundary (topology) ,010103 numerical & computational mathematics ,Type (model theory) ,01 natural sciences ,Domain (mathematical analysis) ,symbols.namesake ,symbols ,0101 mathematics ,Bessel function ,Parametric statistics ,Mathematics - Abstract
This paper is devoted to Hardy type inequalities with remainders for compactly supported smooth functions on open sets in the Euclidean space. We establish new inequalities with weight functions depending on the distance function to the boundary of the domain. One-dimensional L 1 and L p inequalities and their multidimensional analogues are proved. We consider spatial inequalities in open convex domains with the finite inner radius. Constants in these inequalities depend on the roots of parametric Lamb equation for the Bessel function and turn out to be sharp in some particular cases.
- Published
- 2020
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