162 results
Search Results
2. Solutions of fractional gas dynamics equation by a new technique
- Author
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Alicia Cordero Barbero, Juan Ramón Torregrosa Sánchez, and Ali Akgül
- Subjects
Fractional gas dynamics equation ,General Mathematics ,Operators ,010102 general mathematics ,Hilbert space ,General Engineering ,Gas dynamics ,01 natural sciences ,010101 applied mathematics ,symbols.namesake ,symbols ,0101 mathematics ,MATEMATICA APLICADA ,Mathematics ,Mathematical physics - Abstract
[EN] In this paper, a novel technique is formed to obtain the solution of a fractional gas dynamics equation. Some reproducing kernel Hilbert spaces are defined. Reproducing kernel functions of these spaces have been found. Some numerical examples are shown to confirm the efficiency of the reproducing kernel Hilbert space method. The accurate pulchritude of the paper is arisen in its strong implementation of Caputo fractional order time derivative on the classical equations with the success of the highly accurate solutions by the series solutions. Reproducing kernel Hilbert space method is actually capable of reducing the size of the numerical work. Numerical results for different particular cases of the equations are given in the numerical section., This research was partially supported by Spanish Ministerio de Ciencia, Innovacion y Universidades PGC2018-095896-B-C22 and Generalitat Valenciana PROMETEO/2016/089.
- Published
- 2019
3. Fractional powers of the noncommutative Fourier's law by theS‐spectrum approach
- Author
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Stefano Pinton, Samuele Mongodi, Marco M. Peloso, Fabrizio Colombo, Colombo, F, Mongodi, S, Peloso, M, and Pinton, S
- Subjects
S-spectrum ,General Mathematics ,fractional diffusion processe ,General Engineering ,fractional diffusion processes ,Spectrum (topology) ,Noncommutative geometry ,fractional Fourier's law ,symbols.namesake ,Engineering (all) ,Fourier transform ,the S-spectrum approach ,symbols ,Mathematics (all) ,fractional powers of vector operators ,fractional powers of vector operator ,Mathematical physics ,Mathematics - Abstract
Let e ℓ , for ℓ = 1,2,3, be orthogonal unit vectors in R 3 and let Ω ⊂ R 3 be a bounded open set with smooth boundary ∂Ω. Denoting by x a point in Ω, the heat equation, for nonhomogeneous materials, is obtained replacing the Fourier law, given by the following: T = a(x)∂xe1 + b(x)∂ye2 + c(x)∂ze3, into the conservation of energy law, here a, b, c ∶ Ω → R are given functions. With the S-spectrum approach to fractional diffusion processes we determine, in a suitable way, the fractional powers of T. Then, roughly speaking, we replace the fractional powers of T into the conservation of energy law to obtain the fractional evolution equation. This method is important for nonhomogeneous materials where the Fourier law is not simply the negative gradient. In this paper, we determine under which conditions on the coefficients a, b, c ∶ Ω → R the fractional powers of T exist in the sense of the S-spectrum approach. More in general, this theory allows to compute the fractional powers of vector operators that arise in different fields of science and technology. This paper is devoted to researchers working in fractional diffusion and fractional evolution problems, partial differential equations, and noncommutative operator theory.
- Published
- 2019
4. Time-harmonic and asymptotically linear Maxwell equations in anisotropic media
- Author
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Xianhua Tang and Dongdong Qin
- Subjects
General Mathematics ,010102 general mathematics ,Mathematical analysis ,General Engineering ,01 natural sciences ,010101 applied mathematics ,symbols.namesake ,Lipschitz domain ,Maxwell's equations ,Bounded function ,Homogeneous space ,symbols ,Tensor ,Boundary value problem ,0101 mathematics ,Perfect conductor ,Nehari manifold ,Mathematics - Abstract
This paper is focused on following time-harmonic Maxwell equation: ∇×(μ−1(x)∇×u)−ω2e(x)u=f(x,u),inΩ,ν×u=0,on∂Ω, where Ω⊂R3 is a bounded Lipschitz domain, ν:∂Ω→R3 is the exterior normal, and ω is the frequency. The boundary condition holds when Ω is surrounded by a perfect conductor. Assuming that f is asymptotically linear as |u|→∞, we study the above equation by improving the generalized Nehari manifold method. For an anisotropic material with magnetic permeability tensor μ∈R3×3 and permittivity tensor e∈R3×3, ground state solutions are established in this paper. Applying the principle of symmetric criticality, we find 2 types of solutions with cylindrical symmetries in particular for the uniaxial material.
- Published
- 2017
5. Computation of periodic orbits in three-dimensional Lotka-Volterra systems
- Author
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Rubén Poveda and Juan F. Navarro
- Subjects
Series (mathematics) ,General Mathematics ,Computation ,Mathematical analysis ,General Engineering ,Periodic sequence ,010103 numerical & computational mathematics ,Systems modeling ,Symbolic computation ,01 natural sciences ,Poincaré–Lindstedt method ,010101 applied mathematics ,Nonlinear system ,symbols.namesake ,symbols ,Periodic orbits ,0101 mathematics ,Mathematics - Abstract
This paper deals with an adaptation of the Poincare-Lindstedt method for the determination of periodic orbits in three-dimensional nonlinear differential systems. We describe here a general symbolic algorithm to implement the method and apply it to compute periodic solutions in a three-dimensional Lotka-Volterra system modeling a chain food interaction. The sufficient conditions to make secular terms disappear from the approximate series solution are given in the paper.
- Published
- 2017
6. A data assimilation process for linear ill-posed problems
- Author
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X.-M. Yang and Z.-L. Deng
- Subjects
Well-posed problem ,Mathematical optimization ,General Mathematics ,010102 general mathematics ,Bayesian probability ,Posterior probability ,General Engineering ,Markov chain Monte Carlo ,Inverse problem ,01 natural sciences ,010101 applied mathematics ,symbols.namesake ,Data assimilation ,symbols ,Applied mathematics ,Ensemble Kalman filter ,0101 mathematics ,Randomness ,Mathematics - Abstract
In this paper, an iteration process is considered to solve linear ill-posed problems. Based on the randomness of the involved variables, this kind of problems is regarded as simulation problems of the posterior distribution of the unknown variable given the noise data. We construct a new ensemble Kalman filter-based method to seek the posterior target distribution. Despite the ensemble Kalman filter method having widespread applications, there has been little analysis of its theoretical properties, especially in the field of inverse problems. This paper analyzes the propagation of the error with the iteration step for the proposed algorithm. The theoretical analysis shows that the proposed algorithm is convergence. We compare the numerical effect with the Bayesian inversion approach by two numerical examples: backward heat conduction problem and the first kind of integral equation. The numerical tests show that the proposed algorithm is effective and competitive with the Bayesian method. Copyright © 2017 John Wiley & Sons, Ltd.
- Published
- 2017
7. Some inequalities involving Hadamard-type k -fractional integral operators
- Author
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Praveen Agarwal
- Subjects
Inequality ,General Mathematics ,media_common.quotation_subject ,010102 general mathematics ,General Engineering ,Riemann integral ,Type (model theory) ,01 natural sciences ,Fourier integral operator ,Fractional calculus ,010101 applied mathematics ,Algebra ,symbols.namesake ,Hadamard transform ,Improper integral ,symbols ,Daniell integral ,0101 mathematics ,Mathematics ,media_common - Abstract
In this paper, our main aim is to establish some new fractional integral inequalities involving Hadamard-type k-fractional integral operators recently given by Mubeen et al. Furthermore, the paper discusses some of their relevance with known results. Copyright © 2016 John Wiley & Sons, Ltd.
- Published
- 2017
8. Controllability of a class of heat equations with memory in one dimension
- Author
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Xiuxiang Zhou and Hang Gao
- Subjects
0209 industrial biotechnology ,General Mathematics ,010102 general mathematics ,Null (mathematics) ,Mathematical analysis ,General Engineering ,Boundary (topology) ,02 engineering and technology ,01 natural sciences ,Volterra integral equation ,Controllability ,symbols.namesake ,020901 industrial engineering & automation ,Dimension (vector space) ,symbols ,Initial value problem ,State space ,Heat equation ,0101 mathematics ,Mathematics - Abstract
This paper addresses a study of the controllability for a class of heat equations with memory in one spacial dimension. Unlike the classical heat equation, a heat equation with memory in general is not null controllable. There always exists a set of initial values such that the property of the null controllability fails. Also, one does not know whether there are nontrivial initial values, which can be driven to zero with a boundary control. In this paper, we give a characterization of the set of such nontrivial initial values. On the other hand, if a moving control is imposed on this system with memory, we prove the null controllability of it in a suitable state space for any initial value. Copyright © 2016 John Wiley & Sons, Ltd.
- Published
- 2016
9. Asymptotic behavior of solutions of a model derived from the 1‐D Keller–Segel model on the half line
- Author
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Renkun Shi
- Subjects
General Mathematics ,010102 general mathematics ,Mathematical analysis ,General Engineering ,Half-space ,01 natural sciences ,010101 applied mathematics ,symbols.namesake ,Green's function ,symbols ,Boundary value problem ,Half line ,0101 mathematics ,Exponential decay ,Stationary solution ,Constant (mathematics) ,Mathematics - Abstract
In this paper, we are interested in a model derived from the 1-D Keller-Segel model on the half line x > as follows: ut−lux−uxx=−β(uvx)x,x>0,t>0,λv−vxx=u,x>0,t>0,lu(0,t)+ux(0,t)=vx(0,t)=0,t>0,u(x,0)=u0(x),x>0, where l is a constant. Under the conserved boundary condition, we study the asymptotic behavior of solutions. We prove that the problem is always globally and classically solvable when the initial data is small, and moreover, we obtain the decay rates of solutions. The paper mainly deals with the case of l > 0. In this case, the solution to the problem tends to a conserved stationary solution in an exponential decay rate, which is a very different result from the case of l
- Published
- 2016
10. On existence of solutions of differential-difference equations
- Author
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Hai-chou Li
- Subjects
Independent equation ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,General Engineering ,01 natural sciences ,Euler equations ,010101 applied mathematics ,Stochastic partial differential equation ,Examples of differential equations ,Theory of equations ,symbols.namesake ,Simultaneous equations ,symbols ,Applied mathematics ,0101 mathematics ,C0-semigroup ,Differential algebraic equation ,Mathematics - Abstract
This paper applies Nevanlinna theory of value distribution to discuss existence of solutions of certain types of non-linear differential-difference equations such as (5) and (8) given in the succeeding paragraphs. Existence of solutions of differential equations and difference equations can be said to have been well studied, that of differential-difference equations, on the other hand, have been paid little attention. Such mixed type equations have great significance in applications. This paper, in particular, generalizes the Rellich–Wittich-type theorem and Malmquist-type theorem about differential equations to the case of differential-difference equations. Copyright © 2015 John Wiley & Sons, Ltd.
- Published
- 2015
11. On global stability of an HIV pathogenesis model with cure rate
- Author
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Yoshiaki Muroya and Yoichi Enatsu
- Subjects
Lyapunov function ,Mathematical optimization ,General Mathematics ,General Engineering ,Human immunodeficiency virus (HIV) ,medicine.disease_cause ,Stability (probability) ,Upper and lower bounds ,Pathogenesis ,symbols.namesake ,Monotone polygon ,Stability theory ,medicine ,symbols ,Applied mathematics ,Logistic function ,Mathematics - Abstract
In this paper, applying both Lyapunov function techniques and monotone iterative techniques, we establish new sufficient conditions under which the infected equilibrium of an HIV pathogenesis model with cure rate is globally asymptotically stable. By giving an explicit expression for eventual lower bound of the concentration of susceptible CD4+ T cells, we establish an affirmative partial answer to the numerical simulations investigated in the recent paper [Liu, Wang, Hu and Ma, Global stability of an HIV pathogenesis model with cure rate, Nonlinear Analysis RWA (2011) 12: 2947–2961]. Our monotone iterative techniques are applicable for the small and large growth rate in logistic functions for the proliferation rate of healthy and infected CD4+ T cells. Copyright © 2014 John Wiley & Sons, Ltd.
- Published
- 2014
12. On Fourier series for higher order (partial) derivatives of functions
- Author
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Weiming Sun and Zimao Zhang
- Subjects
General Mathematics ,Fourier inversion theorem ,Mathematical analysis ,Fourier sine and cosine series ,General Engineering ,02 engineering and technology ,Trigonometric polynomial ,01 natural sciences ,symbols.namesake ,020303 mechanical engineering & transports ,Generalized Fourier series ,0203 mechanical engineering ,Fourier analysis ,Discrete Fourier series ,0103 physical sciences ,Conjugate Fourier series ,symbols ,010301 acoustics ,Fourier series ,Mathematics - Abstract
This paper is focused on higher order differentiation of Fourier series of functions. By means of Stokes's transformation, the recursion relations between the Fourier coefficients in Fourier series of different order (partial) derivatives of the functions as well as the general formulas for Fourier series of higher order (partial) derivatives of the functions are acquired. And then, the sufficient conditions for term-by-term differentiation of Fourier series of the functions are presented. These findings are subsequently used to reinvestigate the Fourier series methods for linear elasto-dynamical systems. The results given in this paper on the constituent elements, together with their combinatorial modes and numbering, of the sets of coefficients concerning 2rth order linear differential equation with constant coefficients are found to be different from the results deduced by Chaudhuri back in 2002. And it is also shown that the displacement solution proposed by Li in 2009 is valid only when the second order mixed partial derivative of the displacement vanishes at all of the four corners of the rectangular plate. Copyright © 2016 John Wiley & Sons, Ltd.
- Published
- 2016
13. Spatiotemporal patterns in a diffusive predator–prey system with Leslie–Gower term and social behavior for the prey
- Author
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Abdelkader Lakmeche and Fethi Souna
- Subjects
Equilibrium point ,Hopf bifurcation ,General Mathematics ,General Engineering ,Stability (probability) ,Term (time) ,symbols.namesake ,Nonlinear Sciences::Adaptation and Self-Organizing Systems ,Bifurcation theory ,symbols ,Neumann boundary condition ,Quantitative Biology::Populations and Evolution ,Statistical physics ,Constant (mathematics) ,Center manifold ,Mathematics - Abstract
In this paper, we deal with a new approximation of a diffusive predator--prey model with Leslie--Gower term and social behavior for the prey subject to Neumann boundary conditions. A new approach for a predator-prey interaction in the presence of prey social behavior has been considered. Our main topic in this work is to study the influence of the prey's herd shape on the predator-prey interaction in the presence of Leslie--Gower term. First of all, we examine briefly the system without spatial diffusion. By analyzing the distribution of the eigenvalues associated with the constant equilibria, the local stability of the equilibrium points and the existence of Hopf bifurcation have been investigated. Then, the spatiotemporal dynamics introduced by self diffusion was determined, where the existence of the positive solution, Hopf bifurcation, Turing driven instability, Turing-Hopf bifurcation point have been derived. Further, the effect of the prey's herd shape rate on the prey and predator equilibrium densities as well as on the Hopf bifurcating points has been discussed. Finally, by using the normal form theory on the center manifold, the direction and stability of the bifurcating periodic solutions have also been obtained. To illustrate the theoretical results, some graphical representations are given.
- Published
- 2021
14. Strong instability of solitary waves for inhomogeneous nonlinear Schrödinger equations
- Author
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Jian Zhang and Chenglin Wang
- Subjects
symbols.namesake ,Nonlinear system ,Classical mechanics ,General Mathematics ,General Engineering ,symbols ,Instability ,Schrödinger equation ,Mathematics - Abstract
This paper studies the inhomogeneous nonlinear Schrödinger equations, which may model the propagation of laser beams in nonlinear optics. Using the cross-constrained variational method, a sharp condition for global existence is derived. Then, by solving a variational problem, the strong instability of solitary waves of this equation is proved.
- Published
- 2021
15. Stability and Hopf bifurcation analysis of fractional‐order nonlinear financial system with time delay
- Author
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Sunita Chand, Sundarappan Balamuralitharan, and Santoshi Panigrahi
- Subjects
Hopf bifurcation ,Nonlinear system ,symbols.namesake ,Computer simulation ,Laplace transform ,General Mathematics ,General Engineering ,symbols ,Order (ring theory) ,Financial system ,Stability (probability) ,Mathematics - Abstract
In this paper, we study a fractional order time delay for nonlinear financial system. By using Laplace transformation, stability and Hopf bifurcation analysis have been done for the model. Furthermore, numerical simulation has been carried out for better understanding of our results.
- Published
- 2021
16. Higher order stable schemes for stochastic convection–reaction–diffusion equations driven by additive Wiener noise
- Author
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Jean Daniel Mukam and Antoine Tambue
- Subjects
General Mathematics ,Numerical analysis ,finite element method ,General Engineering ,White noise ,Exponential integrator ,VDP::Matematikk og Naturvitenskap: 400::Matematikk: 410 ,Noise (electronics) ,Finite element method ,strong convergence ,Stochastic partial differential equation ,Galerkin projection method ,Nonlinear system ,symbols.namesake ,Wiener process ,symbols ,Applied mathematics ,stochastic convection–reaction–diffusion equations ,additive noise ,exponential integrators ,Mathematics - Abstract
In this paper, we investigate the numerical approximation of stochastic convection-reaction-diffusion equations using two explicit exponential integrators. The stochastic partial differential equation (SPDE) is driven by additive Wiener process. The approximation in space is done via a combination of the standard finite element method and the Galerkin projection method. Using the linear functional of the noise, we construct two accelerated numerical methods, which achieve higher convergence orders. In particular, we achieve convergence rates approximately $1$ for trace class noise and $\frac{1}{2}$ for space-time white noise. These convergences orders are obtained under less regularities assumptions on the nonlinear drift function than those used in the literature for stochastic reaction-diffusion equations. Numerical experiments to illustrate our theoretical results are provided
- Published
- 2021
17. The number of Dirac‐weighted eigenvalues of Sturm–Liouville equations with integrable potentials and an application to inverse problems
- Author
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Xiao Chen and Jiangang Qi
- Subjects
Pure mathematics ,General Mathematics ,010102 general mathematics ,Dirac (software) ,General Engineering ,Dirac delta function ,Sturm–Liouville theory ,Mathematics::Spectral Theory ,01 natural sciences ,010101 applied mathematics ,symbols.namesake ,Dirichlet eigenvalue ,Distribution (mathematics) ,Mathematics - Classical Analysis and ODEs ,Dirichlet boundary condition ,34A06, 34A55, 34B09 ,Classical Analysis and ODEs (math.CA) ,FOS: Mathematics ,symbols ,0101 mathematics ,Complex number ,Eigenvalues and eigenvectors ,Mathematics ,Characteristic polynomial - Abstract
In this paper, we further Meirong Zhang, et al.'s work by computing the number of weighted eigenvalues for Sturm-Liouville equations, equipped with general integrable potentials and Dirac weights, under Dirichlet boundary condition. We show that, for a Sturm-Liouville equation with a general integrable potential, if its weight is a positive linear combination of $n$ Dirac Delta functions, then it has at most $n$ (may be less than $n$, or even be $0$) distinct real Dirichlet eigenvalues, or every complex number is a Dirichlet eigenvalue; in particular, under some sharp condition, the number of Dirichlet eigenvalues is exactly $n$. Our main method is to introduce the concepts of characteristics matrix and characteristics polynomial for Sturm-Liouville problem with Dirac weights, and put forward a general and direct algorithm used for computing eigenvalues. As an application, a class of inverse Dirichelt problems for Sturm-Liouville equations involving single Dirac distribution weights is studied., 23 pages
- Published
- 2021
18. An accelerated hybrid projection method with a self‐adaptive step‐size sequence for solving split common fixed point problems
- Author
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Songxiao Li, Zheng Zhou, and Bing Tan
- Subjects
Sequence ,General Mathematics ,010102 general mathematics ,General Engineering ,Hilbert space ,01 natural sciences ,010101 applied mathematics ,symbols.namesake ,Operator (computer programming) ,Robustness (computer science) ,Convergence (routing) ,Projection method ,symbols ,0101 mathematics ,Focus (optics) ,Algorithm ,Dykstra's projection algorithm ,Mathematics - Abstract
This paper attempts to focus on the split common fixed point problem for demicontractive mappings. We give an accelerated hybrid projection algorithm which combines the hybrid projection method and the inertial technique. The strong convergence theorems of this algorithm are obtained under mild conditions by a self-adaptive step-size sequence, which does not need prior knowledge of operator norms. Some numerical experiments in infinite Hilbert space are provided to illustrate the reliability and robustness of the algorithm and also to compare it with existin
- Published
- 2021
19. Existence and blow‐up studies of a p ( x )‐Laplacian parabolic equation with memory
- Author
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Gnanavel Soundararajan and Lakshmipriya Narayanan
- Subjects
General Mathematics ,Weak solution ,010102 general mathematics ,Mathematical analysis ,Mathematics::Analysis of PDEs ,General Engineering ,Type (model theory) ,01 natural sciences ,Upper and lower bounds ,010101 applied mathematics ,symbols.namesake ,Dirichlet boundary condition ,symbols ,0101 mathematics ,Finite time ,Laplace operator ,Differential inequalities ,Mathematics - Abstract
In this paper, we establish existence and finite time blow up of weak solutions of a parabolic equation of p(x)-Laplacian type with the Dirichlet boundary condition. Moreover, we obtain upper and lower bounds for the blow up time of solutions, by employing concavity method and differential inequality technique respectively.
- Published
- 2020
20. Generalized approximate boundary synchronization for a coupled system of wave equations
- Author
-
Yanyan Wang
- Subjects
General Mathematics ,010102 general mathematics ,General Engineering ,Boundary (topology) ,State (functional analysis) ,Kalman filter ,Wave equation ,01 natural sciences ,Dirichlet distribution ,010101 applied mathematics ,Matrix (mathematics) ,symbols.namesake ,Synchronization (computer science) ,symbols ,Applied mathematics ,0101 mathematics ,Mathematics - Abstract
In this paper, we consider the generalized approximate boundary synchronization for a coupled system of wave equations with Dirichlet boundary controls. We analyse the relationship between the generalized approximate boundary synchronization and the generalized exact boundary synchronization, give a sufficient condition to realize the generalized approximate boundary synchronization and a necessary condition in terms of Kalman’s matrix, and show the meaning of the number of total controls. Besides, by the generalized synchronization decomposition, we define the generalized approximately synchronizable state, and obtain its properties and a sufficient condition for it to be independent of applied boundary controls.
- Published
- 2020
21. The rigorous derivation of unipolar Euler–Maxwell system for electrons from bipolar Euler–Maxwell system by infinity‐ion‐mass limit
- Author
-
Liang Zhao
- Subjects
Thermodynamic equilibrium ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,General Engineering ,Electron ,Decoupling (cosmology) ,01 natural sciences ,Local convergence ,010101 applied mathematics ,symbols.namesake ,Convergence (routing) ,Euler's formula ,symbols ,Convergence problem ,0101 mathematics ,Constant (mathematics) ,Mathematics - Abstract
In the paper, we consider the local-in-time and the global-in-time infinity-ion-mass convergence of bipolar Euler-Maxwell systems by setting the mass of an electron me=1 and letting the mass of an ion mi→∞. We use the method of asymptotic expansions to handle the local-in-time convergence problem and find that the limiting process from bipolar models to unipolar models is actually decoupling, but not the vanishing of equations for the corresponding the other particle. Moreover, when the initial data is sufficiently close to the constant equilibrium state, we establish the global-in-time infinity-ion-mass convergence.
- Published
- 2020
22. Metamaterial acoustics on the Poincaré disk
- Author
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Tung, Michael Ming-Sha
- Subjects
Acoustic analogue models of gravity ,Applications of local differential geometry to the sciences ,General Mathematics ,Poincaré disk model ,General Engineering ,Metamaterial ,Relativity and gravitational theory ,Variational principles of mathematical physics ,Traveling wave solutions ,symbols.namesake ,Classical mechanics ,Poincaré disk ,symbols ,MATEMATICA APLICADA ,Mathematics - Abstract
[EN] Historically, the Poincare disk model has taken a pioneering role in the development of non-Euclidean geometry. But still today, this model is critical as a playground for simulations and new theories. In this paper, we discuss how to implement and simulate acoustic wave phenomena on the Poincare disk with the help of so-called metamaterials. After formally developing a theory based on the acoustic potential for the curved spacetime of the Poincare model, we also provide practical instructions on how to manufacture the appropriate metadevice in a laboratory environment. Finally, as an example, analytical results for the nontrivial radial contributions in concentric wave propagation are derived, and the corresponding numerical predictions are presented., Spanish Ministerio de Economia y Competitividad, the European Regional Development Fund (ERDF), Grant/Award Number: TIN2017-89314-P; Programa de Apoyo a la Investigacion y Desarrollo 2018, Grant/Award Number: PAID-06-18
- Published
- 2020
23. Scattering theory of Dirac operator with the impulsive condition on whole axis
- Author
-
Seyda Solmaz and Elgiz Bairamov
- Subjects
Differential equations ,Dirac system ,Differential equation ,General Mathematics ,General Engineering ,Dirac operator ,symbols.namesake ,Computer Science::Networking and Internet Architecture ,symbols ,Scattering theory ,Scattering matrix ,Computer Science::Cryptography and Security ,Jost solutions ,Mathematics ,Mathematical physics - Abstract
In this paper, we study the Jost solutions of the impulsive Dirac systems (IDS) on entire axis and examine analytic and asymptotic properties of these solutions. Furthermore, we obtain a general form of the scattering matrix of the IDS and its characteristic properties. Finally, we also compare the similar properties for the IDS with the mass on entire axis with an example.
- Published
- 2020
24. Elliptic variational problems with mixed nonlinearities
- Author
-
Qi Han
- Subjects
Pure mathematics ,Measurable function ,General Mathematics ,Multiplicity results ,010102 general mathematics ,General Engineering ,Lebesgue integration ,Lambda ,01 natural sciences ,010101 applied mathematics ,symbols.namesake ,Elliptic curve ,Mathematics - Analysis of PDEs ,FOS: Mathematics ,symbols ,0101 mathematics ,Analysis of PDEs (math.AP) ,Mathematics - Abstract
In this paper, we study the existence and multiplicity results of nontrivial positive solutions to a quasilinear elliptic equation in $\RN$, when $N\geq2$, as \begin{equation} \Lp u+u^{p-1}=\lambda\hspace{0.2mm}k(x)u^{r-1}-h(x)u^{q-1}.\nonumber \end{equation} Here, $h(x),k(x)>0$ are Lebesgue measurable functions, $10$ is a parameter.
- Published
- 2020
25. Extending the choice of starting points for Newton's method
- Author
-
Argyros, Ioannis Konstantinos, Ezquerro, José Antonio, Hernández-Verón, Miguel Ángel, Kim, Young Ik, Magreñán, Ángel Alberto, and 0000-0002-6991-5706
- Subjects
General Mathematics ,010102 general mathematics ,General Engineering ,Lipschitz continuity ,01 natural sciences ,010101 applied mathematics ,symbols.namesake ,symbols ,Order (group theory) ,Applied mathematics ,Center (algebra and category theory) ,0101 mathematics ,Newton's method ,Second derivative ,Mathematics - Abstract
In this paper, we propose a center Lipschitz condition for the second derivative together with the use of restricted domains in order to improve the starting points for Newton's method when compared with previous results. Moreover, we present some numerical examples validating the theoretical results.
- Published
- 2019
26. On the potential in non‐Gaussian chain polymer models
- Author
-
José Luís da Silva, Wolfgang Bock, and Ludwig Streit
- Subjects
anomalous diffusions ,chemistry.chemical_classification ,General Mathematics ,Gaussian ,General Engineering ,Polymer ,chain potential ,generalized ,grey Brownian motion ,symbols.namesake ,Mathematics::Probability ,chain polymer models ,Chain (algebraic topology) ,chemistry ,symbols ,Statistical physics ,Mathematics - Abstract
In this paper, we investigate the potential for a class of non-Gaussian processes so-called generalized grey Brownian motion. We obtain a closed analytic form for the potential as an integral of the M-Wright functions and the Green function. In particular, we recover the special cases of Brownian motion and fractional Brownian motion. In addition, we give the connection to a fractional partial differential equation and its the fundamental solution.
- Published
- 2019
27. Golden ratio algorithms with new stepsize rules for variational inequalities
- Author
-
Yi-bin Xiao, Dang Van Hieu, and Yeol Je Cho
- Subjects
Sequence ,General Mathematics ,010102 general mathematics ,MathematicsofComputing_NUMERICALANALYSIS ,General Engineering ,Hilbert space ,Lipschitz continuity ,01 natural sciences ,Mathematics::Numerical Analysis ,010101 applied mathematics ,symbols.namesake ,Operator (computer programming) ,Rate of convergence ,Convergence (routing) ,Variational inequality ,symbols ,Golden ratio ,0101 mathematics ,Algorithm ,Mathematics - Abstract
In this paper, we introduce two golden ratio algorithms with new stepsize rules for solving pseudomonotone and Lipschitz variational inequalities in finite dimensional Hilbert spaces. The presented stepsize rules allow the resulting algorithms to work without the prior knowledge of the Lipschitz constant of operator. The first algorithm uses a sequence of stepsizes which is previously chosen, diminishing and non-summable. While the stepsizes in the second one are updated at each iteration and by a simple computation. A special point is that the sequence of stepsizes generated by the second algorithm is separated from zero. The convergence as well as the convergence rate of the proposed algorithms are established under some standard conditions. Also, we give several numerical results to show the behavior of the algorithms in comparisons with other algorithms.
- Published
- 2019
28. Special relativistic Fourier transformation and convolutions
- Author
-
Eckhard Hitzer
- Subjects
Pure mathematics ,General Mathematics ,010102 general mathematics ,General Engineering ,Spectral domain ,01 natural sciences ,Convolution ,010101 applied mathematics ,symbols.namesake ,Fourier transform ,Product (mathematics) ,Frequency domain ,symbols ,Point (geometry) ,0101 mathematics ,Linear combination ,Vector space ,Mathematics - Abstract
In this paper we use the steerable special relativistic (space-time) Fourier transform (SFT), and relate the classical convolution of the algebra for space-time $Cl(3,1)$-valued signals over the space-time vector space $\R^{3,1}$, with the (equally steerable) Mustard convolution. A Mustard convolution can be expressed in the spectral domain as the point wise product of the SFTs of the factor functions. In full generality do we express the classical convolution of space-time signals in terms of finite linear combinations of Mustard convolutions, and vice versa the Mustard convolution of space-time signals in terms of finite linear combinations of classical convolutions.
- Published
- 2019
29. The use of partition polynomial series in Laplace inversion of composite functions with applications in fractional calculus
- Author
-
Hamed Taghavian
- Subjects
Laplace inversion ,Laplace transform ,General Mathematics ,Composite number ,General Engineering ,Fractional calculus ,symbols.namesake ,Mittag-Leffler function ,symbols ,Partition (number theory) ,Applied mathematics ,Polynomial series ,Laplace transform inversion ,Mathematics - Abstract
This paper presents an analytical method towards Laplace transform inversion of composite functions with the aid of Bell polynomial series. The presented results are used to derive the exact soluti ...
- Published
- 2019
30. Asymptotic behavior of spectral of Neumann-Poincaré operator in Helmholtz system
- Author
-
Xiaoping Fang, Youjun Deng, and Xiaohong Chen
- Subjects
symbols.namesake ,Mathematics - Analysis of PDEs ,General Mathematics ,Helmholtz free energy ,FOS: Mathematics ,General Engineering ,symbols ,Spectral analysis ,Neumann–Poincaré operator ,Analysis of PDEs (math.AP) ,Mathematical physics ,Mathematics - Abstract
In this paper, we are concerned with the asymptotic behavior of the Neumann-Poincare operator for Helmholtz system. By analyzing the asymptotic behavior of spherical Bessel function near the origin and/or approach higher order, we prove the asymptotic behavior of spectral of Neumann-Poincare operator when frequency is small enough and/or the order is large enough. The results show that spectral of Neumann-Poincare operator is continuous at the origin and converges to zero from the complex plane in general., 12 pages, 11 figures
- Published
- 2018
31. Existence and concentration of positive ground state solutions for nonlinear fractional Schrödinger‐Poisson system with critical growth
- Author
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Ravi P. Agarwal and Kaimin Teng
- Subjects
General Mathematics ,010102 general mathematics ,General Engineering ,01 natural sciences ,010101 applied mathematics ,Nonlinear system ,symbols.namesake ,Mathematics - Analysis of PDEs ,35B38, 35R11 ,symbols ,0101 mathematics ,Poisson system ,Ground state ,Schrödinger's cat ,Mathematics ,Mathematical physics - Abstract
In this paper, we study the following fractional Schr\"{o}dinger-Poisson system involving competing potential functions \begin{equation*} \left\{ \begin{array}{ll} \varepsilon^{2s}(-\Delta)^su+V(x)u+\phi u=K(x)f(u)+Q(x)|u|^{2_s^{\ast}-2}u, & \hbox{in $\mathbb{R}^3$,} \varepsilon^{2t}(-\Delta)^t\phi=u^2,& \hbox{in $\mathbb{R}^3$,} \end{array} \right. \end{equation*} where $\varepsilon>0$ is a small parameter, $f$ is a function of $C^1$ class, superlinear and subcritical nonlinearity, $2_s^{\ast}=\frac{6}{3-2s}$, $s>\frac{3}{4}$, $t\in(0,1)$, $V(x)$ $K(x)$ and $Q(x)$ are positive continuous function. Under some suitable assumptions on $V$, $K$ and $Q$, we prove that there is a family of positive ground state solutions with polynomial growth for sufficiently small $\varepsilon>0$, of which it is concentrating on the set of minimal points of $V(x)$ and the sets of maximal points of $K(x)$ and $Q(x)$. The methods are based on the Nehari manifold, arguments of Brezis-Nirenberg and concentration compactness of P. L. Lions.
- Published
- 2018
32. Blow up of fractional Schrödinger equations on manifolds with nonnegative Ricci curvature
- Author
-
Huali Zhang and Shiliang Zhao
- Subjects
symbols.namesake ,Weight function ,Mathematics - Analysis of PDEs ,35A01 ,General Mathematics ,Mathematics::Analysis of PDEs ,General Engineering ,symbols ,Ricci curvature ,Heat kernel ,Schrödinger equation ,Mathematical physics ,Mathematics - Abstract
In this paper, the well-posedness of Cauchy's problem of fractional Schr\"odinger equations with a power type nonlinearity on $n$-dimensional manifolds with nonnegative Ricci curvature is studied. Under suitable volume conditions, the local solution with initial data in $H^{[\frac{n}{2}]+1}$ will blow up in finite time no matter how small the initial data is, which follows from a new weight function and ODE inequalities. Moreover, the upper-bound of the lifespan can be estimated., Comment: 15 pages. Welcome all comments
- Published
- 2020
33. Hölder regularity for the time fractional Schrödinger equation
- Author
-
Jiqiang Zheng and Xiaoyan Su
- Subjects
symbols.namesake ,Mathematics - Analysis of PDEs ,35R11, 42B15, 35A09 ,General Mathematics ,General Engineering ,symbols ,Mathematics::Spectral Theory ,Mathematics ,Mathematical physics ,Schrödinger equation - Abstract
In this paper, we investigate that the H\"older regularity of solutions to the time fractional Schr\"odinger equation of order $1, Comment: 25 pages
- Published
- 2020
34. Effective numerical evaluation of the double Hilbert transform
- Author
-
Min Ku, Xiaoyun Sun, Ieng Tak Leong, and Pei Dang
- Subjects
Pointwise ,General Mathematics ,010102 general mathematics ,General Engineering ,01 natural sciences ,010101 applied mathematics ,Periodic function ,Quadratic formula ,symbols.namesake ,symbols ,Applied mathematics ,Nyström method ,Hilbert transform ,0101 mathematics ,Remainder ,Energy (signal processing) ,Mathematics ,Trigonometric interpolation - Abstract
In this paper, we propose two methods to compute the double Hilbert transform of periodic functions. First, we establish the quadratic formula of trigonometric interpolation type for double Hilbert transform and obtain an estimation of the remainder. We call this method 2D mechanical quadrature method (2D-MQM). Numerical experiments show that 2D-MQM outperforms the library function “hilbert” in Matlab when the values of the functions being handled are very large or approach to infinity. Second, we propose a complex analytic method to calculate the double Hilbert transform, which is based on the 2D adaptive Fourier decomposition, and the method is called as 2D-HAFD. In contrast to the pointwise approximation, 2D-HAFD provides explicit rational functional approximations and is valid for all signals of finite energy.
- Published
- 2020
35. Stability results of a distributed problem involving Bresse system with history and/or Cattaneo law under fully Dirichlet or mixed boundary conditions
- Author
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Mouhammad Ghader, Farah Abdallah, and Ali Wehbe
- Subjects
Polynomial ,General Mathematics ,010102 general mathematics ,General Engineering ,Thermal conduction ,01 natural sciences ,Stability (probability) ,Displacement (vector) ,Dirichlet distribution ,010101 applied mathematics ,symbols.namesake ,Exponential stability ,Law ,Dirichlet boundary condition ,symbols ,Boundary value problem ,0101 mathematics ,Mathematics - Abstract
In this paper, we study the stability of a one-dimensional Bresse system with infinite memory type control and/or with heat conduction given by Cattaneo's law acting in the shear angle displacement. When the thermal effect vanishes, the system becomes elastic with memory term acting on one equation. Unlike [6], [10], and [22], we consider the interesting case of fully Dirichlet boundary conditions. Indeed, under equal speed of propagation condition, we establish the exponential stability of the system. However, in the natural physical case when the speeds of propagation are different, using a spectrum method, we show that the Bresse system is not uniformly stable. In this case, we establish a polynomial energy decay rate. Our study is valid for all other mixed boundary conditions and generalizes that of [6], [10], and [22].
- Published
- 2018
36. Existence of nontrivial solutions for Schrödinger-Kirchhoff type equations with critical or supercritical growth
- Author
-
Quanqing Li, Xian Wu, and Kaimin Teng
- Subjects
Kirchhoff type ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,General Engineering ,01 natural sciences ,Supercritical fluid ,010101 applied mathematics ,symbols.namesake ,Variational method ,Convergence (routing) ,symbols ,0101 mathematics ,Schrödinger's cat ,Mathematics - Abstract
In this paper, we study the following Schrodinger-Kirchhoff–type equation with critical or supercritical growth −(a+b∫R3|∇u|2dx)△u+V(x)u=f(x,u)+λ|u|p−2u,x∈R3, where a>0, b>0, λ>0, and p≥6. Under some suitable conditions, we prove that the equation has a nontrivial solution for small λ>0 by variational method. Moreover, we regard b as a parameter and obtain a convergence property of the nontrivial solution as b↘0. Our main contribution is related to the fact that we are able to deal with the case p>6.
- Published
- 2017
37. Wiman‐Valiron theory for higher dimensional polynomial Cauchy‐Riemann equations
- Author
-
R. De Almeida and Rolf Sören Kraußhar
- Subjects
Discrete mathematics ,Hypercomplex number ,Polynomial ,General Mathematics ,Operator (physics) ,010102 general mathematics ,General Engineering ,Cauchy–Riemann equations ,Context (language use) ,01 natural sciences ,010101 applied mathematics ,Set (abstract data type) ,symbols.namesake ,Iterated function ,Core (graph theory) ,symbols ,0101 mathematics ,Mathematics - Abstract
In this paper, we introduce different kinds of growth orders for the set of entire solutions to the most general framework of higher-dimensional polynomial Cauchy-Riemann equations ∏i=1p(D−λi)kif=0, where D:=∂f∂x0+∑i=1nei∂f∂xi is the hypercomplex Cauchy-Riemann operator, λi are arbitrarily chosen nonzero complex constants, and ki are arbitrarily chosen positive integers. The core ingredient is a projection formula that establishes a relation to the ki-monogenic component functions, which are null-solutions to iterates of the Cauchy-Riemann operator that we studied in earlier works. Furthermore, we briefly outline the analogies of the Lindelof-Pringsheim theorem in this context.
- Published
- 2017
38. An efficient method for fractional nonlinear differential equations by quasi-Newton's method and simplified reproducing kernel method
- Author
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Jing Niu, Minqiang Xu, and Yingzhen Lin
- Subjects
General Mathematics ,010102 general mathematics ,Mathematical analysis ,MathematicsofComputing_NUMERICALANALYSIS ,General Engineering ,Fréchet derivative ,01 natural sciences ,Nonlinear differential equations ,Local convergence ,010101 applied mathematics ,Split-step method ,Nonlinear system ,symbols.namesake ,Kernel method ,ComputingMethodologies_SYMBOLICANDALGEBRAICMANIPULATION ,Convergence (routing) ,symbols ,0101 mathematics ,Newton's method ,Mathematics - Abstract
An efficient method for nonlinear fractional differential equations is proposed in this paper. This method consists of 2 steps. First, we linearize the nonlinear operator equation by quasi-Newton's method, which is based on Frechet derivative. Then we solve the linear fractional differential equations by the simplified reproducing kernel method. The convergence of the quasi-Newton's method is discussed for the general nonlinear case as well. Finally, some numerical examples are presented to illustrate accuracy, efficiency, and simplicity of the method.
- Published
- 2017
39. A new family of 7 stages, eighth-order explicit Numerov-type methods
- Author
-
Ch. Tsitouras and T. E. Simos
- Subjects
Constant coefficients ,010304 chemical physics ,General Mathematics ,010102 general mathematics ,General Engineering ,Function (mathematics) ,Type (model theory) ,Expression (computer science) ,01 natural sciences ,Set (abstract data type) ,symbols.namesake ,0103 physical sciences ,Taylor series ,symbols ,Calculus ,Initial value problem ,0101 mathematics ,Algebraic number ,Mathematics - Abstract
In this paper, we consider the integration of the special second-order initial value problem. Hybrid Numerov methods are used, which are constructed in the sense of Runge-Kutta ones. Thus, the Taylor expansions at the internal points are matched properly in the final expression. A new family of such methods attaining eighth algebraic order is given at a cost of only 7 function evaluations per step. The new family provides us with an extra parameter, which is used to increase phase-lag order to 18. We proceed with numerical tests over a standard set of problems for these cases. Appendices implementing the symbolic construction of the methods and derivation of their coefficients are also given.
- Published
- 2017
40. Existence and limit behavior of prescribed L 2 -norm solutions for Schrödinger-Poisson-Slater systems in R3
- Author
-
Qi Zhang, Xincai Zhu, and Shuai Li
- Subjects
Pure mathematics ,General Mathematics ,010102 general mathematics ,Minimization problem ,General Engineering ,Poisson distribution ,01 natural sciences ,010101 applied mathematics ,Combinatorics ,Constraint (information theory) ,symbols.namesake ,symbols ,Limit (mathematics) ,0101 mathematics ,Schrödinger's cat ,Mathematics - Abstract
In this paper, we study constraint minimizers of the following L2−critical minimization problem: e(N):=inf{E(u),u∈H1(R3)and∫R3|u|2dx=N>0}, where E(u) is the Schrodinger-Poisson-Slater functional E(u):=∫R3|∇u|2dx−12∫R3∫R3u2(y)u2(x)|x−y|dydx−35∫R3m(x)|u|103dx, and N denotes the mass of the particles in the Schrodinger-Poisson-Slater system. We prove that e(N) admits minimizers for N N∗, where Q(x) is the unique positive solution of △u−u+u73=0 in R3. Some results on the existence and nonexistence of minimizers for e(N∗) are also established. Further, when e(N∗) does not admit minimizers, the limit behavior of minimizers as N↗N∗ is also analyzed rigorously.
- Published
- 2017
41. Ground state of solutions for a class of fractional Schrödinger equations with critical Sobolev exponent and steep potential well
- Author
-
Liuyang Shao and Haibo Chen
- Subjects
General Mathematics ,Operator (physics) ,media_common.quotation_subject ,010102 general mathematics ,Mathematical analysis ,General Engineering ,Function (mathematics) ,Infinity ,01 natural sciences ,Schrödinger equation ,Fractional calculus ,010101 applied mathematics ,Sobolev space ,symbols.namesake ,symbols ,Exponent ,0101 mathematics ,Ground state ,Mathematics ,media_common - Abstract
In this paper, we study the following fractional Schrodinger equations: (−△)αu+λV(x)u=κ|u|q−2u|x|s+β|u|2α∗−2u,u∈Hα(RN),N⩾3,(1) where (−△)α is the fractional Laplacian operator with α∈(0,1),2≤q≤2α,s∗=2(N−s)N−2α≤2α∗=2NN−2α, 0≤s≤2α, λ>0, κ and β are real parameter. 2α∗ is the critical Sobolev exponent. We prove a fractional Sobolev-Hardy inequality and use it together with concentration compact theory to get a ground state solution. Moreover, concentration behaviors of nontrivial solutions are obtained when the coefficient of the potential function tends to infinity.
- Published
- 2017
42. A graph-theoretic method to stabilize the delayed coupled systems on networks based on periodically intermittent control
- Author
-
Chiping Zhang, Beibei Guo, and Yu Xiao
- Subjects
Lyapunov function ,0209 industrial biotechnology ,Computer simulation ,General Mathematics ,Intermittent control ,General Engineering ,Structure (category theory) ,Graph theory ,Topology (electrical circuits) ,02 engineering and technology ,Stability (probability) ,Matrix (mathematics) ,symbols.namesake ,020901 industrial engineering & automation ,Control theory ,0202 electrical engineering, electronic engineering, information engineering ,symbols ,020201 artificial intelligence & image processing ,Mathematics - Abstract
This paper mainly focus on the exponential stabilization problem of coupled systems on networks with mixed time-varying delays. Periodically intermittent control is used to control the coupled systems on networks with mixed time-varying delays. Moreover, based on the graph theory and Lyapunov method, two different kinds of stabilization criteria are derived, which are in the form of Lyapunov-type theorem and coefficients-type criterion, respectively. These laws reveal that the stability has a close relationship with the topology structure of the networks. In addition, as a subsequent result, a decision theorem is also presented. It is straightforward to show the stability of original system can be determined by that of modified system with added absolute value into the coupling weighted-value matrix. Finally, the feasibility and validity of the obtained results are demonstrated by several numerical simulation figures.
- Published
- 2017
43. Existence of multiplicity harmonic and subharmonic solutions for second-order quasilinear equation via Poincaré-Birkhoff twist theorem
- Author
-
Jingli Ren and Zhibo Cheng
- Subjects
Subharmonic ,General Mathematics ,010102 general mathematics ,Time map ,Mathematical analysis ,General Engineering ,Multiplicity (mathematics) ,01 natural sciences ,010101 applied mathematics ,symbols.namesake ,Poincaré conjecture ,symbols ,0101 mathematics ,Twist ,Analysis method ,Mathematics - Abstract
In this paper, we investigate the existence and multiplicity of harmonic and subharmonic solutions for second-order quasilinear equation (ϕp(x′))′+g(x)=e(t), where ϕp:R→R,ϕp(u)=|u|p−2u,p>1, g satisfies the superlinear condition at infinity. We prove that the given equation possesses harmonic and subharmonic solutions by using the phase-plane analysis methods and a generalized version of the Poincare-Birkhoff twist theorem.
- Published
- 2017
44. Positive ground state of coupled systems of Schrödinger equations in R2 involving critical exponential growth
- Author
-
João Marcos do Ó and José Carlos de Albuquerque
- Subjects
General Mathematics ,010102 general mathematics ,Mathematical analysis ,General Engineering ,Type (model theory) ,Coupling (probability) ,01 natural sciences ,Schrödinger equation ,Exponential function ,010101 applied mathematics ,symbols.namesake ,Nonlinear system ,Maximum principle ,symbols ,0101 mathematics ,Nehari manifold ,Ground state ,Mathematics - Abstract
In this paper, we study the existence of a positive ground state solution to the following coupled system of nonlinear Schrodinger equations: −Δu+V1(x)u=f1(x,u)+λ(x)v,x∈R2,−Δv+V2(x)v=f2(x,v)+λ(x)u,x∈R2, where the nonlinearities f1(x,s) and f2(x,s) are superlinear at infinity and have exponential critical growth of the Trudinger-Moser type. The potentials V1(x) and V2(x) are nonnegative and satisfy a condition involving the coupling term λ(x), namely, λ(x)2
- Published
- 2017
45. Dynamics of a ratio-dependent stage-structured predator-prey model with delay
- Author
-
Yongli Song, Tao Yin, and Hongying Shu
- Subjects
Hopf bifurcation ,Steady state ,General Mathematics ,Dynamics (mechanics) ,General Engineering ,Structure (category theory) ,01 natural sciences ,Stability (probability) ,Instability ,010305 fluids & plasmas ,010101 applied mathematics ,symbols.namesake ,Control theory ,0103 physical sciences ,symbols ,Quantitative Biology::Populations and Evolution ,Applied mathematics ,0101 mathematics ,Reduction (mathematics) ,Center manifold ,Mathematics - Abstract
In this paper, we investigate the dynamics of a time-delay ratio-dependent predator-prey model with stage structure for the predator. This predator-prey system conforms to the realistically biological environment. The existence and stability of the positive equilibrium are thoroughly analyzed, and the sufficient and necessary conditions for the stability and instability of the positive equilibrium are obtained for the case without delay. Then, the influence of delay on the dynamics of the system is investigated using the geometric criterion developed by Beretta and Kuang.[26] We show that the positive steady state can be destabilized through a Hopf bifurcation and there exist stability switches under some conditions. The formulas determining the direction and the stability of Hopf bifurcations are explicitly derived by using the center manifold reduction and normal form theory. Finally, some numerical simulations are performed to illustrate and expand our theoretical results.
- Published
- 2017
46. Generalized Bessel functions: Theory and their applications
- Author
-
Mohammad Reza Eslahchi, Mehdi Dehghan, and Hassan Khosravian-Arab
- Subjects
Pure mathematics ,Cylindrical harmonics ,Bessel process ,Differential equation ,Bessel filter ,General Mathematics ,Mathematical analysis ,General Engineering ,010103 numerical & computational mathematics ,01 natural sciences ,010101 applied mathematics ,symbols.namesake ,Orthogonality ,Bessel polynomials ,Struve function ,symbols ,0101 mathematics ,Bessel function ,Mathematics - Abstract
This paper presents 2 new classes of the Bessel functions on a compact domain [0,T] as generalized-tempered Bessel functions of the first- and second-kind which are denoted by GTBFs-1 and GTBFs-2. Two special cases corresponding to the GTBFs-1 and GTBFs-2 are considered. We first prove that these functions are as the solutions of 2 linear differential operators and then show that these operators are self-adjoint on suitable domains. Some interesting properties of these sets of functions such as orthogonality, completeness, fractional derivatives and integrals, recursive relations, asymptotic formulas, and so on are proved in detail. Finally, these functions are performed to approximate some functions and also to solve 3 practical differential equations of fractionalorders.
- Published
- 2017
47. An asymptotic expansion for the semi‐infinite sum of Dirac‐ δ functions
- Author
-
Jaime Klapp, Otto Rendón, and Leonardo Di G. Sigalotti
- Subjects
Generalized function ,Laplace transform ,Series (mathematics) ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,Dirac (software) ,General Engineering ,01 natural sciences ,Dirac comb ,symbols.namesake ,Distribution (mathematics) ,0103 physical sciences ,symbols ,0101 mathematics ,010306 general physics ,Asymptotic expansion ,Series expansion ,Mathematics - Abstract
In this paper, we derive an asymptotic expansion for the semi-infinite sum of Dirac-δ functions centered at discrete equidistant points defined by the set Na={x∈R:∃n∈N∧x=na,∀a>0}. The method relies on the Laplace transform of the semi-infinite sum of Dirac-δ functions. The derived series distribution takes the form of the Euler-Maclaurin summation when the distributions are defined for complex or real-valued continuous functions over the interval [0,∞). For n=1, the series expansion contributes with a term equal to δ(x)/2, which survives in the limit when a→0+. This term represents a correction term, which is in general omitted in calculations of the density of states of quantum confined systems by finite-size effects.
- Published
- 2017
48. Nodal bound state of nonlinear problems involving the fractional Laplacian
- Author
-
Longbo Lv and Wei Long
- Subjects
General Mathematics ,010102 general mathematics ,Mathematical analysis ,General Engineering ,Positive function ,01 natural sciences ,Schrödinger equation ,010101 applied mathematics ,Nonlinear system ,symbols.namesake ,Integer ,Bound state ,symbols ,0101 mathematics ,Fractional Laplacian ,Nonlinear Schrödinger equation ,Mathematics - Abstract
This paper is concerned with the following nonlinear fractional Schrodinger equation e2s(−Δ)su+V(x)u=|u|p−2u,inRN, where e>0 is a small parameter, V(x) is a positive function, 0 2s). Under some suitable conditions, we prove that for any positive integer k, one can construct a nonradial sign-changing (nodal) solutions with exactly k maximum points and k minimum points near the local minimum point of V(x).
- Published
- 2017
49. Evolutionary generation of high-order, explicit, two-step methods for second-order linear IVPs
- Author
-
Ch. Tsitouras and T. E. Simos
- Subjects
Constant coefficients ,010304 chemical physics ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,General Engineering ,Structure (category theory) ,Function (mathematics) ,Wave equation ,01 natural sciences ,symbols.namesake ,Differential evolution ,0103 physical sciences ,Taylor series ,symbols ,Initial value problem ,0101 mathematics ,Algebraic number ,Mathematics - Abstract
In this paper, we consider the integration of systems of second-order linear inhomogeneous initial value problems with constant coefficients. Hybrid Numerov methods are used that are constructed in the sense of Runge-Kutta ones. Thus, the Taylor expansions at the internal points are matched properly in the final expression. We present the order conditions taking advantage of the special structure of the problem at hand. These equations are solved using differential evolution technique, and we present a method with algebraic order eighth at a cost of only 5 function evaluations per step. Numerical results over some linear problems, especially arising from the semidiscretization of the wave equation indicate the superiority of the new method.
- Published
- 2017
50. Global exponential stability of periodic solutions in a nonsmooth model of hematopoiesis with time-varying delays
- Author
-
Yanxiang Tan and Mengmeng Zhang
- Subjects
010101 applied mathematics ,Lyapunov function ,symbols.namesake ,Exponential stability ,Control theory ,General Mathematics ,010102 general mathematics ,General Engineering ,symbols ,0101 mathematics ,Dynamical system ,01 natural sciences ,Mathematics - Abstract
In this paper, we study a model of hematopoiesis with time-varying delays and discontinuous harvesting, which is described by a nonsmooth dynamical system. Based on a newly developed method, nonsmooth analysis, and the generalized Lyapunov method, some new delay-dependent criteria are established to ensure the existence and global exponential stability of positive periodic solutions. Moreover, an example with numerical simulations is presented to demonstrate the effectiveness of theoretical results. Copyright © 2017 John Wiley & Sons, Ltd.
- Published
- 2017
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