2,705 results
Search Results
52. How Many Weak-Keys Exist in T-310 ?
- Author
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Matteo Scarlata, Marios Georgiou, and Nicolas T. Courtois
- Subjects
related-key attacks ,021110 strategic, defence & security studies ,Thesaurus (information retrieval) ,Information retrieval ,unbalanced Feistel ciphers ,Cold War ,General Mathematics ,generalised linear cryptanalysis ,collision resistance ,05 social sciences ,linear cryptanalysis ,0211 other engineering and technologies ,block ciphers ,T-310 ,Block ciphers ,differential cryptanalysis ,weak key attacks ,02 engineering and technology ,050601 international relations ,0506 political science ,Mathematics - Abstract
T-310 is an important Cold War cipher. The cipher is extremely complex and it outputs extremely few bits from the internal state. A recent paper [Courtois, N. T.: Decryption oracle slide attacks on T-310, Cryptologia, 42 (2018), no. 3, 191–204] shows an example of a highly anomalous key such that T-310 can be broken by a slide attack with a decryption oracle. In this paper, we show that the same attacks are ALSO possible for regular keys which satisfy all the official KT1 requirements. Two other recent papers [Courtois, N. T.—Georgiou, M.—Scarlata, M.: Slide attacks and LC-weak keys in T-310, Cryptologia 43 (2019), no. 3, 175–189]; [Courtois, N. T.—Oprisanu, M. B.—Schmeh, K.: Linear cryptanalysis and block cipher design in East Germany in the 1970s, Cryptologia (published online), December 5, 2018] show that some of the KT1 keys are very weak w.r.t. Linear Cryptanalysis. In this paper, we show that a vast number of such weak keys exist and study the exact pre-conditions which make them weak. In addition we introduce a new third class of weak keys for RKDC (Related-Key Differential Cryptanalysis). We show that the original designers in the 1970s have ensured that these RKDC properties cannot happen for 4 rounds. We have discovered that these properties can happen for as few as 5 rounds for some keys, and for 10 to 16 rounds they become hard to avoid. The main reason why we study weak keys is to show that none of these properties occur by accident, rather that they are governed by precise pre-conditions which guarantee their existence, and countless other keys with the same properties exist. Eventually, this is how interesting attacks can be found., Tatra Mountains Mathematical Publications, 73 (1)
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- 2019
53. Dynamics of two-species delayed competitive stage-structured model described by differential-difference equations
- Author
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Guoxin Liu, Sufang Han, Yaqin Li, Lianglin Xiong, and Tianwei Zhang
- Subjects
lcsh:Mathematics ,General Mathematics ,010102 general mathematics ,Dynamics (mechanics) ,almost periodic solution ,Differential difference equations ,34k20 ,stability ,92b05 ,92d25 ,lcsh:QA1-939 ,stage structure ,01 natural sciences ,coincidence degree ,010101 applied mathematics ,34k13 ,competitive model ,Applied mathematics ,Stage (hydrology) ,0101 mathematics ,Structured model ,Mathematics - Abstract
Overf the last few years, by utilizing Mawhin’s continuation theorem of coincidence degree theory and Lyapunov functional, many scholars have been concerned with the global asymptotical stability of positive periodic solutions for the non-linear ecosystems. In the real world, almost periodicity is usually more realistic and more general than periodicity, but there are scarcely any papers concerning the issue of the global asymptotical stability of positive almost periodic solutions of non-linear ecosystems. In this paper we consider a kind of delayed two-species competitive model with stage structure. By means of Mawhin’s continuation theorem of coincidence degree theory, some sufficient conditions are obtained for the existence of at least one positive almost periodic solutions for the above model with nonnegative coefficients. Furthermore, the global asymptotical stability of positive almost periodic solution of the model is also studied. The work of this paper extends and improves some results in recent years. An example and simulations are employed to illustrate the main results of this paper.
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- 2019
54. Augmented, free and tensor generalized digroups
- Author
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Raúl Velásquez, José Gregorio Rodríguez-Nieto, and Olga Salazar-Diaz
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20n99 ,Pure mathematics ,Semidirect product ,20e06 ,General Mathematics ,010102 general mathematics ,010103 numerical & computational mathematics ,01 natural sciences ,digroups ,group actions ,Group action ,free and tensor groups ,Tensor (intrinsic definition) ,QA1-939 ,20a05 ,20e34 ,semidirect product ,0101 mathematics ,20b10 ,Mathematics ,20a10 - Abstract
The concept of generalized digroup was proposed by Salazar-Díaz, Velásquez and Wills-Toro in their paper “Generalized digroups” as a non trivial extension of groups. In this way, many concepts and results given in the category of groups can be extended in a natural form to the category of generalized digroups. The aim of this paper is to present the construction of the free generalized digroup and study its properties. Although this construction is vastly different from the one given for the case of groups, we will use this concept, the classical construction for groups and the semidirect product to construct the tensor generalized digroup as well as the semidirect product of generalized digroups. Additionally, we give a new structural result for generalized digroups using compatible actions of groups and an equivariant map from a group set to the group corresponding to notions of associative dialgebras and augmented racks.
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- 2019
55. Approximation by modified Jain–Baskakov operators
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Marius Mihai Birou, Vishnu Narayan Mishra, and Preeti Sharma
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Baskakov operator ,General Mathematics ,010102 general mathematics ,Applied mathematics ,Basis function ,Asymptotic formula ,010103 numerical & computational mathematics ,0101 mathematics ,01 natural sciences ,Modulus of continuity ,Mathematics - Abstract
In the present paper, we discuss the approximation properties of Jain–Baskakov operators with parameter c. The paper deals with the modified forms of the Baskakov basis functions. Some direct results are established, which include the asymptotic formula, error estimation in terms of the modulus of continuity and weighted approximation. Also, we construct the King modification of these operators, which preserves the test functions e 0 {e_{0}} and e 1 {e_{1}} . It is shown that these King type operators provide a better approximation order than some Baskakov–Durrmeyer operators for continuous functions defined on some closed intervals.
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- 2019
56. Mild solution of stochastic partial differential equation with nonlocal conditions and noncompact semigroups
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Ahmed Abdelmonem, Pengyu Chen, Xuping Zhang, and Yongxiang Li
- Subjects
010101 applied mathematics ,Stochastic partial differential equation ,General Mathematics ,010102 general mathematics ,Applied mathematics ,0101 mathematics ,01 natural sciences ,Mathematics - Abstract
The aim of this paper is to discuss the existence of mild solutions for a class of semilinear stochastic partial differential equation with nonlocal initial conditions and noncompact semigroups in a real separable Hilbert space. Combined with the theory of stochastic analysis and operator semigroups, a generalized Darbo’s fixed point theorem and a new estimation technique of the measure of noncompactness, we obtained the existence of mild solutions under the situation that the nonlinear term and nonlocal function satisfy some appropriate local growth conditions and a noncompactness measure condition. In addition, the condition of uniformly continuity of the nonlinearity is not required and also the strong restriction on the constants in the condition of noncompactness measure is completely deleted in this paper. An example to illustrate the feasibility of the main results is also given.
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- 2019
57. On complete convergence for weighted sums of arrays of rowwise END random variables and its statistical applications
- Author
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Junjie Lin, Yi Wu, Xiaohan Bao, and Xuejun Wang
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010104 statistics & probability ,General Mathematics ,010102 general mathematics ,Convergence (routing) ,Applied mathematics ,0101 mathematics ,01 natural sciences ,Random variable ,Mathematics - Abstract
In this paper, the complete convergence for the weighted sums of arrays of rowwise extended negatively dependent (END, for short) random variables is established under some mild conditions. In addition, the Marcinkiewicz-Zygmund type strong law of large numbers for arrays of rowwise END random variables is also obtained. The result obtained in the paper generalizes and improves some corresponding ones for independent random variables and some dependent random variables in some extent. By using the complete convergence that we established, we further study the complete consistency for the weighted estimator in a nonparametric regression model based on END errors.
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- 2019
58. Computational uncertainty quantification for random non-autonomous second order linear differential equations via adapted gPC: a comparative case study with random Fröbenius method and Monte Carlo simulation
- Author
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Juan Carlos Cortés, Marc Jornet, and Julia Calatayud
- Subjects
Non-autonomous and random dynamical systems ,Adaptive generalized Polynomial Chaos ,General Mathematics ,Comparative case ,Monte Carlo method ,random Fröbenius method ,Random Frobenius method ,010103 numerical & computational mathematics ,01 natural sciences ,93e03 ,non-autonomous and random dynamical systems ,computational uncertainty quantification ,Stochastic Galerkin projection technique ,Linear differential equation ,34f05 ,QA1-939 ,Applied mathematics ,Order (group theory) ,60h35 ,0101 mathematics ,Uncertainty quantification ,Mathematics ,Final version ,Computational uncertainty quantification ,random fröbenius method ,93E03 ,adaptive generalized Polynomial Chaos ,stochastic Galerkin projection technique ,010101 applied mathematics ,Frobenius method ,34F05 ,60H35 ,MATEMATICA APLICADA - Abstract
[EN] This paper presents a methodology to quantify computationally the uncertainty in a class of differential equations often met in Mathematical Physics, namely random non-autonomous second-order linear differential equations, via adaptive generalized Polynomial Chaos (gPC) and the stochastic Galerkin projection technique. Unlike the random Frobenius method, which can only deal with particular random linear differential equations and needs the random inputs (coefficients and forcing term) to be analytic, adaptive gPC allows approximating the expectation and covariance of the solution stochastic process to general random second-order linear differential equations. The random inputs are allowed to functionally depend on random variables that may be independent or dependent, both absolutely continuous or discrete with infinitely many point masses. These hypotheses include a wide variety of particular differential equations, which might not be solvable via the random Frobenius method, in which the random input coefficients may be expressed via a Karhunen-Loeve expansion., This work has been supported by the Spanish Ministerio de Economia y Competitividad grant MTM2017-89664-P. Marc Jornet acknowledges the doctorate scholarship granted by Programa de Ayudas de Investigacion y Desarrollo (PAID), Universitat Politecnica de Valencia. The authors are grateful for the valuable comments raised by the reviewer, which have improved the final version of the paper.
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- 2018
59. Computation of Definite Integral Over Repeated Integral
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Katarína Tvrdá and Mária Minárová
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Class (set theory) ,General Mathematics ,Computation ,Gauss ,Principal (computer security) ,Cauchy distribution ,Applied mathematics ,Integral element ,Type (model theory) ,Mathematics - Abstract
The tasks involving repeated integral occur from time to time in technical practice. This paper introduces the research of authors in the field of repeated integrals within the required class of functions. Authors focus on the definite integral over repeated integral and they develop a tool for its computation. It involves two principal steps, analytical and numerical step. In the analytical step, the definite integral over a repeated integral is decomposed into n integrals and then the Cauchy form is used for further rearrangement. Numerical step involves Gauss type integration slightly modified by the authors. Several examples illustrating the operation of both analytical and numerical steps of the method are provided in the paper.
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- 2018
60. Regularized Coherence Enhancing Filtering
- Author
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Olga Stašová and Zuzana Krivá
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Nonlinear system ,General Mathematics ,010102 general mathematics ,0202 electrical engineering, electronic engineering, information engineering ,Applied mathematics ,020201 artificial intelligence & image processing ,02 engineering and technology ,0101 mathematics ,01 natural sciences ,Mathematics ,Coherence (physics) ,Convolution - Abstract
The paper deals with the nonlinear tensor diffusion which yields a coherence improvement. It is very appropriate for images with flow-like structures. Two convolutions are used in the construction of diffusion tensor for such a model, see [Drblíková, O.—Mikula, K.: Convergence analysis of finite volume scheme for nonlinear tensor anisotropic diffusion in image processing, SIAM J. Numer. Anal. 46 (2007), 37–60], [Weickert, J.: Coherence-enhancing diffusion filtering, Int. J. Comput. Vis. 31 (1999), 111–127]. In this paper we introduce the third supplemental convolution in order to enhance the diffusion strategy. First, we briefly present the classical coherence enhancing model and explain our modification. Then the discrete scheme is provided. The core of the paper consists in numerical experiments. Benefits of the additional convolution are discussed and illustrated in the figures.
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- 2018
61. Alternative proofs of some formulas for two tridiagonal determinants
- Author
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Ai-Qi Liu and Feng Qi
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Thesaurus (information retrieval) ,Tridiagonal matrix ,alternative proof ,inverse ,General Mathematics ,010102 general mathematics ,primary 47b36 ,Mathematical proof ,Computer Science::Numerical Analysis ,01 natural sciences ,Mathematics::Numerical Analysis ,010101 applied mathematics ,Algebra ,Computer Science::Mathematical Software ,QA1-939 ,tridiagonal determinant ,0101 mathematics ,tridiagonal matrix ,Mathematics ,secondary 11b39, 11b83,11c08, 11c20, 11y55, 15b36, 26c99 - Abstract
In the paper, the authors provide five alternative proofs of two formulas for a tridiagonal determinant, supply a detailed proof of the inverse of the corresponding tridiagonal matrix, and provide a proof for a formula of another tridiagonal determinant. This is a companion of the paper [F. Qi, V. Čerňanová,and Y. S. Semenov, Some tridiagonal determinants related to central Delannoy numbers, the Chebyshev polynomials, and the Fibonacci polynomials, Politehn. Univ. Bucharest Sci. Bull. Ser. A Appl. Math. Phys. 81 (2019), in press.
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- 2018
62. Existence of Positive Bounded Solutions of System of Three Dynamic Equations with Neutral Term on Time Scales
- Author
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Urszula Ostaszewska, Ewa Schmeidel, and Małgorzata Zdanowicz
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Combinatorics ,0209 industrial biotechnology ,020901 industrial engineering & automation ,Generalization ,General Mathematics ,Bounded function ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,02 engineering and technology ,Dynamic equation ,Term (time) ,Mathematics - Abstract
In this paper the system of three dynamic equations with neutral term in the following form $$ \left\{ \begin{array}{l} ( x (t) + p(t) x (u_1 (t) ) )^\delta = a(t) f (y(u_2(t))) \\ y^\delta (t) = b(t) g (z( u_3(t) ) ) \\ z^\delta(t) = c(t) h( x( u_4(t) ) ) \right. \end{array} $$ on time scales is considered. The aim of this paper is to present sucient conditions for the existence of positive bounded positive solutions of the considered system for 0 < p(t) const < 1. The main tool of the proof of presented here result is Krasnoselskii's xed point theorem. Also, the useful generalization of the Arzela-Ascoli theorem on times scales to the three dimensional case is proved.
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- 2018
63. Idempotents, group membership and their applications
- Author
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Štefan Porubský
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Algebra ,Group membership ,General Mathematics ,010102 general mathematics ,010103 numerical & computational mathematics ,0101 mathematics ,01 natural sciences ,Mathematics - Abstract
Š. Schwarz in his paper [SCHWARZ, Š.:Zur Theorie der Halbgruppen, Sborník prác Prírodovedeckej fakulty Slovenskej univerzity v Bratislave, Vol. VI, Bratislava, 1943, 64 pp.] proved the existence of maximal subgroups in periodic semigroups and a decade later he brought into play the maximal subsemigroups and thus he embodied the idempotents in the structural description of semigroups [SCHWARZ, Š.:Contribution to the theory of torsion semigroups, Czechoslovak Math. J.3(1) (1953), 7–21]. Later in his papers he showed that a proper description of these structural elements can be used to (re)prove many useful and important results in algebra and number theory. The present paper gives a survey of selected results scattered throughout the literature where an semigroup approach based on tools like idempotent, maximal subgroup or maximal subsemigroup either led to a new insight into the substance of the known results or helped to discover new approach to solve problems. Special attention will be given to some disregarded historical connections between semigroup and ring theory.
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- 2018
64. On the equivalence between noncollapsing and bounded entropy for ancient solutions to the Ricci flow
- Author
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Yongjia Zhang
- Subjects
0209 industrial biotechnology ,Pure mathematics ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,Ricci flow ,02 engineering and technology ,01 natural sciences ,020901 industrial engineering & automation ,Bounded function ,Mathematics::Differential Geometry ,0101 mathematics ,Entropy (arrow of time) ,Mathematics - Abstract
As a continuation of a previous paper, we prove Perelman’s assertion, that is, for ancient solutions to the Ricci flow with bounded nonnegative curvature operator, uniformly bounded entropy is equivalent to κ-noncollapsing on all scales. We also establish an equality between the asymptotic entropy and the asymptotic reduced volume, which is a result similar to a paper by Xu (2017), where he assumes the Type I curvature bound.
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- 2018
65. Solution of the Ulam stability problem for Euler–Lagrange k-quintic mappings
- Author
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Syed Abdul Mohiuddine, Abdullah Alotaibi, and John Michael Rassias
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Linear map ,symbols.namesake ,Pure mathematics ,Quadratic equation ,Probability theory ,General Mathematics ,Functional equation ,Euler's formula ,symbols ,Type (model theory) ,Stability (probability) ,Mathematics ,Quintic function - Abstract
The “oldest quartic” functional equation f ( x + 2 y ) + f ( x - 2 y ) = 4 [ f ( x + y ) + f ( x - y ) ] - 6 f ( x ) + 24 f ( y ) f(x+2y)+f(x-2y)=4[f(x+y)+f(x-y)]-6f(x)+24f(y) was introduced and solved by the second author of this paper (see J. M. Rassias, Solution of the Ulam stability problem for quartic mappings, Glas. Mat. Ser. III 34(54) 1999, 2, 243–252). Similarly, an interesting “quintic” functional equation was introduced and investigated by I. G. Cho, D. Kang and H. Koh, Stability problems of quintic mappings in quasi-β-normed spaces, J. Inequal. Appl. 2010 2010, Article ID 368981, in the following form: 2 f ( 2 x + y ) + 2 f ( 2 x - y ) + f ( x + 2 y ) + f ( x - 2 y ) = 20 [ f ( x + y ) + f ( x - y ) ] + 90 f ( x ) . 2f(2x+y)+2f(2x-y)+f(x+2y)+f(x-2y)=20[f(x+y)+f(x-y)]+90f(x). In this paper, we generalize this “Cho–Kang–Koh equation” by introducing pertinent Euler–Lagrange k-quintic functional equations, and investigate the “Ulam stability” of these new k-quintic functional mappings.
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- 2018
66. Group schemes and local densities of ramified hermitian lattices in residue characteristic 2. Part II
- Author
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Sungmun Cho
- Subjects
Pure mathematics ,Residue (complex analysis) ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,0103 physical sciences ,ComputingMethodologies_DOCUMENTANDTEXTPROCESSING ,010307 mathematical physics ,0101 mathematics ,01 natural sciences ,Hermitian matrix ,Mathematics - Abstract
This paper is the complementary work of [S. Cho, Group schemes and local densities of ramified hermitian lattices in residue characteristic 2: Part I, Algebra Number Theory 10 2016, 3, 451–532]. Ramified quadratic extensions E / F {E/F} , where F is a finite unramified field extension of ℚ 2 {\mathbb{Q}_{2}} , fall into two cases that we call Case 1 and Case 2. In our previous work, we obtained the local density formula for a ramified hermitian lattice in Case 1. In this paper, we obtain the local density formula for the remaining Case 2, by constructing a smooth integral group scheme model for an appropriate unitary group. Consequently, this paper, combined with [W. T. Gan and J.-K. Yu, Group schemes and local densities, Duke Math. J. 105 2000, 3, 497–524] and our previous work, allows the computation of the mass formula for any hermitian lattice ( L , H ) {(L,H)} , when a base field is unramified over ℚ {\mathbb{Q}} at a prime ( 2 ) {(2)} .
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- 2018
67. Homogeneous Finsler spaces and the flag-wise positively curved condition
- Author
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Ming Xu and Shaoqiang Deng
- Subjects
Mathematics - Differential Geometry ,22E46, 53C30 ,Pure mathematics ,Applied Mathematics ,General Mathematics ,Flag (linear algebra) ,010102 general mathematics ,Lie group ,Space (mathematics) ,01 natural sciences ,Differential Geometry (math.DG) ,0103 physical sciences ,Lie algebra ,FOS: Mathematics ,Compact Lie algebra ,Tangent space ,Mathematics::Differential Geometry ,0101 mathematics ,Invariant (mathematics) ,010306 general physics ,Hopf conjecture ,Mathematics - Abstract
In this paper, we introduce the flag-wise positively curved condition for Finsler spaces (the (FP) Condition), which means that in each tangent plane, we can find a flag pole in this plane such that the corresponding flag has positive flag curvature. Applying the Killing navigation technique, we find a list of compact coset spaces admitting non-negatively curved homogeneous Finsler metrics satisfying the (FP) Condition. Using a crucial technique we developed previously, we prove that most of these coset spaces cannot be endowed with positively curved homogeneous Finsler metrics. We also prove that any Lie group whose Lie algebra is a rank $2$ non-Abelian compact Lie algebra admits a left invariant Finsler metric satisfying the (FP) condition. As by-products, we find the first example of non-compact coset space $S^3\times \mathbb{R}$ which admits homogeneous flag-wise positively curved Finsler metrics. Moreover, we find some non-negatively curved Finsler metrics on $S^2\times S^3$ and $S^6\times S^7$ which satisfy the (FP) condition, as well as some flag-wise positively curved Finsler metrics on $S^3\times S^3$, shedding some light on the long standing general Hopf conjecture., 23 pages. The newest version has strengthened the main results in the paper, and provides more examples. We add a short survey on the most recent progress inspired by this paper in the introduction section
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- 2018
68. Maia type fixed point theorems for Ćirić-Prešić operators
- Author
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Margareta-Eliza Balazs
- Subjects
primary 54h25 ,Pure mathematics ,two metrics ,General Mathematics ,ćirić-prešić ,Fixed-point theorem ,010103 numerical & computational mathematics ,Type (model theory) ,01 natural sciences ,secondary 47h10 ,maia ,010101 applied mathematics ,fixed point ,QA1-939 ,0101 mathematics ,Mathematics - Abstract
The main aim of this paper is to obtain Maia type fixed point results for Ćirić-Prešić contraction condition, following Ćirić L. B. and Prešić S. B. result proved in [Ćirić L. B.; Prešić S. B. On Prešić type generalization of the Banach contraction mapping principle, Acta Math. Univ. Comenian. (N.S.), 2007, v 76, no. 2, 143–147] and Luong N. V. and Thuan N. X. result in [Luong, N. V., Thuan, N. X., Some fixed point theorems of Prešić-Ćirić type, Acta Univ. Apulensis Math. Inform., No. 30, (2012), 237–249]. We unified these theorems with Maia’s fixed point theorem proved in [Maia, Maria Grazia. Un’osservazione sulle contrazioni metriche. (Italian) Rend. Sem. Mat. Univ. Padova 40 1968 139–143] and the obtained results are proved is the present paper. An example is also provided.
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- 2018
69. On generalized nonlinear Euler-Bernoulli Beam type equations
- Author
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Rabah Khaldi and Assia Guezane-Lakoud
- Subjects
General Mathematics ,Euler bernoulli beam ,upper and lower solutions method ,010102 general mathematics ,Mathematical analysis ,34b15 ,34a08 ,Type (model theory) ,01 natural sciences ,010101 applied mathematics ,Nonlinear system ,QA1-939 ,euler-bernouli beam equation ,0101 mathematics ,existence of solution ,Mathematics - Abstract
This paper is devoted to the study of a nonlinear Euler-Bernoulli Beam type equation involving both left and right Caputo fractional derivatives. Differently from the approaches of the other papers where they established the existence of solution for the linear Euler-Bernoulli Beam type equation numerically, we use the lower and upper solutions method with some new results on the monotonicity of the right Caputo derivative. Furthermore, we give the explicit expression of the upper and lower solutions. A numerical example is given to illustrate the obtained results.
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- 2018
70. Space-time L 2 estimates, regularity and almost global existence for elastic waves
- Author
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Kunio Hidano and Dongbing Zha
- Subjects
010101 applied mathematics ,Applied Mathematics ,General Mathematics ,Space time ,010102 general mathematics ,Mathematical analysis ,0101 mathematics ,01 natural sciences ,Mathematics - Abstract
In this paper, we first establish a kind of weighted space-time L 2 {L^{2}} estimate, which belongs to Keel–Smith–Sogge-type estimates, for perturbed linear elastic wave equations. This estimate refines the corresponding one established by the second author [D. Zha, Space-time L 2 L^{2} estimates for elastic waves and applications, J. Differential Equations 263 2017, 4, 1947–1965] and is proved by combining the methods in the former paper, the first author, Wang and Yokoyama’s paper [K. Hidano, C. Wang and K. Yokoyama, On almost global existence and local well posedness for some 3-D quasi-linear wave equations, Adv. Differential Equations 17 2012, 3–4, 267–306] and some new ingredients. Then, together with some weighted Sobolev inequalities, this estimate is used to show a refined version of almost global existence of classical solutions for nonlinear elastic waves with small initial data. Compared with former almost global existence results for nonlinear elastic waves due to John [F. John, Almost global existence of elastic waves of finite amplitude arising from small initial disturbances, Comm. Pure Appl. Math. 41 1988, 5, 615–666] and Klainerman and Sideris [S. Klainerman and T. C. Sideris, On almost global existence for nonrelativistic wave equations in 3D, Comm. Pure Appl. Math. 49 1996, 307–321], the main innovation of our result is that it considerably improves the amount of regularity of initial data, i.e., the Sobolev regularity of initial data is assumed to be the smallest among all the admissible Sobolev spaces of integer order in the standard local existence theory. Finally, in the radially symmetric case, we establish the almost global existence of a low regularity solution for every small initial data in H 3 × H 2 {H^{3}\times H^{2}} .
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- 2018
71. On the constancy of signs and order of magnitude of Fourier–Haar coefficients
- Author
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V. Tsagareishvili and Larry Gogoladze
- Subjects
Modulus of smoothness ,Concave function ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,Haar ,010103 numerical & computational mathematics ,01 natural sciences ,symbols.namesake ,Fourier transform ,symbols ,0101 mathematics ,Order of magnitude ,Mathematics - Abstract
In the paper, we investigate the relation between the properties of functions and their Fourier–Haar coefficients. We show that for some classes of functions Fourier–Haar coefficients have constant signs and order of magnitude. In 1964, Golubov proved in [B. I. Golubov, On Fourier series of continuous functions with respect to a Haar system (in Russian), Izv. Akad. Nauk SSSR Ser. Mat. 28 1964, 1271–1296] that if f ( x ) ∈ C ( 0 , 1 ) {f(x)\in C(0,1)} , then its Fourier–Haar coefficients have constant signs when f ( x ) {f(x)} is a nonincreasing function on [ 0 , 1 ] {[0,1]} , and in some cases those coefficients have a certain order of magnitude. In the present paper, we continue to investigate the properties of functions which follow from the behavior of their Fourier–Haar coefficients.
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- 2018
72. A general fixed point theorem for two pairs of mappings satisfying a mixed implicit relation
- Author
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Valeriu Popa and Alina-Mihaela Patriciu
- Subjects
010101 applied mathematics ,Pure mathematics ,Relation (database) ,General Mathematics ,010102 general mathematics ,Fixed-point theorem ,0101 mathematics ,Fixed point ,01 natural sciences ,Mathematics - Abstract
In this paper a general fixed point theorem for mappings with a new type of common limit range property satisfying a mixed implicit relation is proved. In the last part of the paper, as application, some fixed point results for mappings satisfying contractive conditions of integral type and for φ-contractive mappings are obtained.
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- 2018
73. On some generalized Painlevé and Hayman type equations with meromorphic solutions in a bounded domain
- Author
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G. Barsegian and Wenjun Yuan
- Subjects
010101 applied mathematics ,Pure mathematics ,General Mathematics ,Bounded function ,010102 general mathematics ,0101 mathematics ,Type (model theory) ,01 natural sciences ,Domain (mathematical analysis) ,Mathematics ,Meromorphic function - Abstract
The value distribution and, in particular, the numbers of a-points, have not been studied for meromorphic functions which are solutions of some complex differential equations in a given domain. Instead, the numbers of good a-points and Ahlfors islands, which play to a certain extend a role similar to that of the numbers of a-points, have been considered in some recent papers. In this paper, we consider meromorphic functions in a given domain, which are the solutions of some higher order equations and largely generalize the solutions of Painlevé equations 3–6. We give the upper bounds for the numbers of good a-points and Ahlfors islands of similar solutions.
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- 2018
74. Singularly Perturbed Fractional Schrödinger Equation Involving a General Critical Nonlinearity
- Author
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Jianjun Zhang, Hua Jin, and Wenbin Liu
- Subjects
010101 applied mathematics ,symbols.namesake ,Nonlinear system ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,symbols ,Statistical and Nonlinear Physics ,0101 mathematics ,01 natural sciences ,Nonlinear Schrödinger equation ,Mathematics ,Schrödinger equation - Abstract
In this paper, we are concerned with the existence and concentration phenomena of solutions for the following singularly perturbed fractional Schrödinger problem: ε 2 s ( - Δ ) s u + V ( x ) u = f ( u ) in ℝ N , \varepsilon^{2s}(-\Delta)^{s}u+V(x)u=f(u)\quad\text{in }\mathbb{R}^{N}, where N > 2 s {N>2s} and the nonlinearity f has critical growth. By using the variational approach, we construct a localized bound-state solution concentrating around an isolated component of the positive minimum point of V as ε → 0 {\varepsilon\rightarrow 0} . Our result improves the study made in [X. He and W. Zou, Existence and concentration result for the fractional Schrödinger equations with critical nonlinearities, Calc. Var. Partial Differential Equations 55 2016, 4, Article ID 91], in the sense that, in the present paper, the Ambrosetti–Rabinowitz condition and the monotonicity condition on f ( t ) / t {f(t)/t} are not required.
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- 2018
75. Cardinal functions of the hyperspace of convergent sequences
- Author
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Roberto Pichardo-Mendoza, David Maya, and Patricia Pellicer-Covarrubias
- Subjects
010101 applied mathematics ,Combinatorics ,Hyperspace ,General Mathematics ,010102 general mathematics ,0101 mathematics ,01 natural sciences ,Mathematics - Abstract
The symbol 𝓢 c (X) denotes the hyperspace of all nontrivial convergent sequences in a Hausdorff space X. This hyperspace is endowed with the Vietoris topology. In the current paper, we compare the cellularity, the tightness, the extent, the dispersion character, the net weight, the i-weight, the π-weight, the π-character, the pseudocharacter and the Lindelöf number of 𝓢 c (X) with the corresponding cardinal function of X. We also answer a question posed by the authors in a previous paper.
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- 2018
76. Second hankel determinat for certain analytic functions satisfying subordinate condition
- Author
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Levent Budak and Erhan Deniz
- Subjects
010101 applied mathematics ,Algebra ,General Mathematics ,010102 general mathematics ,0101 mathematics ,01 natural sciences ,Mathematics ,Analytic function - Abstract
In this paper, we introduce and investigate the following subclass 1 + 1 γ z f ′ ( z ) + λ z 2 f ″ ( z ) λ z f ′ ( z ) + ( 1 − λ ) f ( z ) − 1 ≺ φ ( z ) 0 ≤ λ ≤ 1 , γ ∈ C ∖ { 0 } $$\begin{array}{} \displaystyle 1+\frac{1}{\gamma }\left( \frac{zf'(z)+\lambda z^{2}f''(z)}{\lambda zf'(z)+(1-\lambda )f(z)}-1\right) \prec \varphi (z)\qquad\left( 0\leq \lambda \leq 1,\gamma \in \mathbb{C} \smallsetminus \{0\}\right) \end{array} $$ of analytic functions, φ is an analytic function with positive real part in the unit disk 𝔻, satisfying φ (0) = 1, φ '(0) > 0, and φ (𝔻) is symmetric with respect to the real axis. We obtain the upper bound of the second Hankel determinant | a2a4− a 3 2 $\begin{array}{} a^2_3 \end{array} $ | for functions belonging to the this class is studied using Toeplitz determinants. The results, which are presented in this paper, would generalize those in related works of several earlier authors.
- Published
- 2018
77. On the formula of Cohen–Vogt relatively pointed topological semi-simplicial sets
- Author
-
Leonard Mdzinarishvili
- Subjects
010101 applied mathematics ,Pure mathematics ,General Mathematics ,010102 general mathematics ,0101 mathematics ,01 natural sciences ,Mathematics - Abstract
In the papers [1] and [6], for an inverse sequence of pointed topological spaces and fibrations preserving the base points E = E 1 ← p 1 E 2 ← p 2 ⋯ ← p m E m + 1 , E=E_{1}\xleftarrow{p_{1}}E_{2}\xleftarrow{p_{2}}\cdots\xleftarrow{p_{m}}E_{m+1}, there exists an exact sequence * → lim ← ( 1 ) [ X , Ω E m ] → [ X , lim ← E ] → lim ← ( 1 ) [ X , E m ] → * . *\rightarrow{\varprojlim}^{(1)}[X,\Omega E_{m}]\rightarrow[X,\varprojlim E]% \rightarrow{\varprojlim}^{(1)}[X,E_{m}]\rightarrow*. In the present paper, for an inverse sequence of pointed topological semi-simplicial sets and fibrations preserving base points E ¯ = E ¯ ← p 1 1 E ¯ ← p 2 2 ⋯ ← p m E ¯ ← m + 1 ⋯ , \underline{E}=\underline{E}{}_{1}\xleftarrow{p_{1}}\underline{E}{}_{2}% \xleftarrow{p_{2}}\cdots\xleftarrow{p_{m}}\underline{E}{}_{m+1}\xleftarrow{% \hphantom{p_{1}}}\cdots, an analogous formula is proved.
- Published
- 2018
78. Rational homology and homotopy of high-dimensional string links
- Author
-
Paul Arnaud Songhafouo Tsopméné and Victor Turchin
- Subjects
Homotopy group ,Pure mathematics ,Conjecture ,Hochschild homology ,Direct sum ,Applied Mathematics ,General Mathematics ,Homotopy ,010102 general mathematics ,Codimension ,Homology (mathematics) ,Mathematics::Algebraic Topology ,01 natural sciences ,Mathematics::K-Theory and Homology ,0103 physical sciences ,Isotopy ,010307 mathematical physics ,0101 mathematics ,Mathematics - Abstract
Arone and the second author showed that when the dimensions are in the stable range, the rational homology and homotopy of the high-dimensional analogues of spaces of long knots can be calculated as the homology of a direct sum of finite graph-complexes that they described explicitly. They also showed that these homology and homotopy groups can be interpreted as the higher-order Hochschild homology, also called Hochschild–Pirashvili homology. In this paper, we generalize all these results to high-dimensional analogues of spaces of string links. The methods of our paper are applicable in the range when the ambient dimension is at least twice the maximal dimension of a link component plus two, which in particular guarantees that the spaces under study are connected. However, we conjecture that our homotopy graph-complex computes the rational homotopy groups of link spaces always when the codimension is greater than two, i.e. always when the Goodwillie–Weiss calculus is applicable. Using Haefliger’s approach to calculate the groups of isotopy classes of higher-dimensional links, we confirm our conjecture at the level of π 0 {\pi_{0}} .
- Published
- 2018
79. On Φ-Dedekind, Φ-Prüfer and Φ-Bezout modules
- Author
-
Shahram Motmaen and Ahmad Yousefian Darani
- Subjects
010101 applied mathematics ,Pure mathematics ,General Mathematics ,010102 general mathematics ,ComputingMethodologies_DOCUMENTANDTEXTPROCESSING ,0101 mathematics ,01 natural sciences ,Mathematics - Abstract
In this paper, we introduce some classes of R-modules that are closely related to the classes of Prüfer, Dedekind and Bezout modules. Let R be a commutative ring with identity and set ℍ = { M ∣ M is an R -module and Nil ( M ) is a divided prime submodule of M } . \mathbb{H}=\bigl{\{}M\mid M\text{ is an }R\text{-module and }\mathrm{Nil}(M)% \text{ is a divided prime submodule of }M\bigr{\}}. For an R-module M ∈ ℍ {M\in\mathbb{H}} , set T = ( R ∖ Z ( R ) ) ∩ ( R ∖ Z ( M ) ) {T=(R\setminus Z(R))\cap(R\setminus Z(M))} , 𝔗 ( M ) = T - 1 M {\mathfrak{T}(M)=T^{-1}M} and P = ( Nil ( M ) : R M ) {P=(\mathrm{Nil}(M):_{R}M)} . In this case, the mapping Φ : 𝔗 ( M ) → M P {\Phi:\mathfrak{T}(M)\to M_{P}} given by Φ ( x / s ) = x / s {\Phi(x/s)=x/s} is an R-module homomorphism. The restriction of Φ to M is also an R-module homomorphism from M into M P {M_{P}} given by Φ ( x ) = x / 1 {\Phi(x)=x/1} for every x ∈ M {x\in M} . A nonnil submodule N of M is said to be Φ-invertible if Φ ( N ) {\Phi(N)} is an invertible submodule of Φ ( M ) {\Phi(M)} . Moreover, M is called a Φ-Prüfer module if every finitely generated nonnil submodule of M is Φ-invertible. If every nonnil submodule of M is Φ-invertible, then we say that M is a Φ-Dedekind module. Furthermore, M is said to be a Φ-Bezout module if Φ ( N ) {\Phi(N)} is a principal ideal of Φ ( M ) {\Phi(M)} for every finitely generated submodule N of the R-module M. The paper is devoted to the study of the properties of Φ-Prüfer, Φ-Dedekind and Φ-Bezout R-modules.
- Published
- 2018
80. A stochastic differential game of low carbon technology sharing in collaborative innovation system of superior enterprises and inferior enterprises under uncertain environment
- Author
-
Baizhou Li and Shi Yin
- Subjects
low carbon technology sharing ,021103 operations research ,General Mathematics ,05 social sciences ,0211 other engineering and technologies ,91a23 ,chemistry.chemical_element ,02 engineering and technology ,Innovation system ,92d25 ,chemistry ,90b50 ,superior and inferior enterprises ,uncertain environment ,0502 economics and business ,Differential game ,QA1-939 ,stochastic differential game ,collaborative innovation ,Carbon ,Mathematics ,050203 business & management ,Industrial organization - Abstract
Considering the fact that the development of low carbon economy calls for the low carbon technology sharing between interested enterprises, this paper study a stochastic differential game of low carbon technology sharing in collaborative innovation system of superior enterprises and inferior enterprises. In the paper, we consider the random interference factors that include the uncertain external environment and the internal understanding limitations of decision maker. In the model, superior enterprises and inferior enterprises are separated entities, and they play Stacklberg master-slave game, Nash non-cooperative game, and cooperative game, respectively. We discuss the feedback equilibrium strategies of superior enterprises and inferior enterprises, and it is found that some random interference factors in sharing system can make the variance of improvement degree of low carbon technology level in the cooperation game higher than the variance in the Stackelberg game, and the result of Stackelberg game is similar to the result of Nash game. Additionally, a government subsidy incentive and a special subsidy that inferior enterprises give to superior enterprises are proposed.
- Published
- 2018
81. On some boundary value problems for the heat equation in a non-regular type of a prism of ℝ N+1
- Author
-
Arezki Kheloufi
- Subjects
010101 applied mathematics ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,Heat equation ,Regular type ,Prism ,Boundary value problem ,0101 mathematics ,01 natural sciences ,Mathematics - Abstract
This paper is devoted to the analysis of the boundary value problem ∂ t u - Δ u = f {\partial_{t}u-\Delta u=f} , with an N-dimensional space variable, subject to a Dirichlet–Robin type boundary condition on the lateral boundary of the domain. The problem is settled in a noncylindrical domain of the form Q = { ( t , x 1 ) ∈ ℝ 2 : 0 < t < T , φ 1 ( t ) < x 1 < φ 2 ( t ) } × ∏ i = 1 N - 1 ] 0 , b i [ Q=\{(t,x_{1})\in\mathbb{R}^{2}:0 , where φ 1 {\varphi_{1}} and φ 2 {\varphi_{2}} are smooth functions. One of the main issues of the paper is that the domain can possibly be non-regular; for instance, the significant case when φ 1 ( 0 ) = φ 2 ( 0 ) {\varphi_{1}(0)=\varphi_{2}(0)} is allowed. We prove well-posedness results for the problem in a number of different settings and under natural assumptions on the coefficients and on the geometrical properties of the domain. This work is an extension of the one-dimensional case studied in [4].
- Published
- 2017
82. Fourier transforms of powers of well-behaved 2D real analytic functions
- Author
-
Michael Greenblatt
- Subjects
Class (set theory) ,Pure mathematics ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,Newton polygon ,Function (mathematics) ,01 natural sciences ,Subclass ,symbols.namesake ,Fourier transform ,Mathematics - Classical Analysis and ODEs ,0103 physical sciences ,Classical Analysis and ODEs (math.CA) ,FOS: Mathematics ,symbols ,010307 mathematical physics ,42B20 ,0101 mathematics ,Analytic function ,Mathematics - Abstract
This paper is a companion paper to [G4], where sharp estimates are proven for Fourier transforms of compactly supported functions built out of two-dimensional real-analytic functions. The theorems of [G4] are stated in a rather general form. In this paper, we expand on the results of [G4] and show that there is a class of "well-behaved" functions that contains a number of relevant examples for which such estimates can be explicitly described in terms of the Newton polygon of the function. We will further see that for a subclass of these functions, one can prove noticeably more precise estimates, again in an explicitly describable way., 13 pages
- Published
- 2017
83. Application and Misapplication of the Czechoslovak STP Cipher During WWII
- Author
-
Štefan Porubský
- Subjects
Positive response ,Cipher ,business.industry ,General Mathematics ,World War II ,Lieutenant colonel ,Military intelligence ,Library science ,Christian ministry ,Cryptography ,business ,Mathematics - Abstract
Lieutenant colonel Karol Cigáň (1921-2005), head of the cryptographic unit of the Czechoslovak Ministry of National Defence in the period 1949-1958 was after discharging from this position in Prague relocated to an insignificant and substandard command position at a district military administration in Slovakia. His cryptographic experience was of no use in his new position. To profit from his previous experience as a high qualified cryptographer he started to study the accessible literature and archive materials about the usage of the Czechoslovak cipher systems during the WWII. The result of this his activity were some manuscripts where he deciphered and analyzed some Czechoslovak military wireless telegrams. His critical analysis and his conclusions did not meet an understanding or a positive response of historians and were nor accepted for publication. He had no other chance as to send them to archives. Unfortunately only one (in two copies) and a collection of small notes survived. The aim of this paper is to make decisive technical parts of manuscript [K. Cigáň: Impacts of the decryption of the cipher system of the Czechoslovak Ministry of Defence in London from the years 1940-1945 on the resistance movement. Archive of the Slovak National Uprising, Banská Bystrica, Slovakia, Document collection (Fond) V, manuscript no. S36/90, 46 pp.] about the usage of the socalled STP cipher accessible. Thereby we complement the paper [Š. Porubský: STP cipher of the Czechoslovak in-exile Ministry of Defence in London during WWII, in: Proc. of EuroHCC’17, 3rd European Historical Ciphers Colloq., Smolenice Castle, Slovakia, 2017 (J. von zur Gathen et al., eds.), Slovak Univ. of Technology in Bratislava, 2017, pp. 47-66] where the part of this manuscript containing Cigáň’s method for solving STP cipher which he calls “mathematical” is published. To put Cigáň’s analysis and comment into their historical framework we briefly outline the history of Czechoslovak military intelligence activities with emphasis on their cryptological component.
- Published
- 2017
84. Wolfenbüttel, a Minor German Duchy But a Major Center of Cryptology in the Early Modern Period
- Author
-
Gerhard F. Strasser
- Subjects
021110 strategic, defence & security studies ,Anagram ,General Mathematics ,05 social sciences ,0211 other engineering and technologies ,02 engineering and technology ,Minor (academic) ,Pseudonym ,050601 international relations ,language.human_language ,0506 political science ,German ,Early modern period ,language ,Slovak ,Center (algebra and category theory) ,Duchy ,Classics ,Mathematics - Abstract
This paper proposes to highlight cryptographic activities from 1540 to about 1680 at a small duchy—Brunswick-Luneburg in northern Germany, not too far from Hanover. The analysis shall proceed chronologically and present some relevant examples from the 16 th century before focusing on the most important German cryptological author of his time, Duke August the Younger (1579-1666). His 1624 book of 493 pages, Cryptomenytices et Cryptographiae Libri IX [1] (Ill. 1) [DS1] became the cryptological standard work of the 17 th century and will be the focus of this paper. Some interesting cryptograms of his successors and a totally surprising, new authorship of the duke’s handbook around 1900 will round out this analysis. *Paper presented at the Third European Historical Ciphers Colloquium from May 15-17, 2017, at the Slovak Academy of Sciences, Smolenice Castle near Bratislava. [1] Luneburg: Gebruder Stern 1624. Duke August published the folio-size book under the pseudonym of “Gustavus Selenus“—“Gustavus“ is easily recognized as an anagram of “Augustus“ while “Selenus“ refers to the lunar goddess Selene and plays upon the name “Luneburg“ or “Lunaeburg,“ the “lunar“ or “moon castle“ where the work was printed. See Strasser: “Duke August the Younger of Brunswick-Luneburg (Gustavus Selenus) and His Cryptological Activities.“ In: Cryptologia 7 (1983), 193-217. [DS1] Old No. 3
- Published
- 2017
85. Generalized Key Substitution Attacks on Message Recovery Signatures
- Author
-
Atsushi Fujioka
- Subjects
Scheme (programming language) ,021110 strategic, defence & security studies ,Theoretical computer science ,Generalization ,General Mathematics ,Substitution (logic) ,0211 other engineering and technologies ,02 engineering and technology ,Signature (logic) ,Discrete logarithm ,Key (cryptography) ,computer ,Mathematics ,computer.programming_language - Abstract
This paper treats effectiveness of the generalized key substitution attacks, and practical measures against them. The generalized key substitution attacks are proposed as a generalization of the key substitution attacks to examine the security of the signature schemes adopted in ISO/IEC (1st CD) 14888-3, which standardizes appendix-type signature schemes based on the discrete logarithm problem. This paper examines the message recovery signature schemes based on the discrete logarithm problem, adopted in ISO/IEC 9796-3:2006, and shows that all but one scheme are vulnerable to the generalized key substitution attacks.
- Published
- 2017
86. A generalization of a graph theory Mertens’ theorem: Galois covering case
- Author
-
Iwao Sato, Seiken Saito, and Takehiro Hasegawa
- Subjects
Mertens conjecture ,Discrete mathematics ,Applied Mathematics ,General Mathematics ,Fundamental theorem of Galois theory ,010102 general mathematics ,Galois group ,0102 computer and information sciences ,01 natural sciences ,Embedding problem ,Combinatorics ,Differential Galois theory ,symbols.namesake ,010201 computation theory & mathematics ,Mertens function ,Mertens' theorems ,symbols ,Galois extension ,0101 mathematics ,Mathematics - Abstract
In 1874, Franz Mertens proved the so-called Mertens’ theorem, and in 1974, Kenneth S. Williams showed Mertens’ theorem associated with a character. In a previous paper, we presented a graph-theoretic analogue to Williams’ theorem. In this paper, we generalize our previous work in the sense that a character is extended to a representation. To our knowledge, a number-theoretic analogue to our result is not yet known. So, we expect that, by using our methods, it can be proven in the future.
- Published
- 2017
87. Period relations for cusp forms of GSp4
- Author
-
Harald Grobner and Ronnie Sebastian
- Subjects
Applied Mathematics ,General Mathematics ,010102 general mathematics ,0103 physical sciences ,Cusp (anatomy) ,010307 mathematical physics ,0101 mathematics ,Geodesy ,01 natural sciences ,Period (music) ,Mathematics - Abstract
Let F be a totally real number field and let π be a cuspidal automorphic representation of GSp 4 ( 𝔸 F ) {\mathrm{GSp_{4}}(\mathbb{A}_{F})} , which contributes irreducibly to coherent cohomology. If π has a Bessel model, we may attach a period p ( π ) {p(\pi)} to this datum. In the present paper, which is Part I in a series of two, we establish a relation of these Bessel periods p ( π ) {p(\pi)} and all of their twists p ( π ⊗ ξ ) {p(\pi\otimes\xi)} under arbitrary algebraic Hecke characters ξ. In the appendix, we show that ( 𝔤 , K ) {(\mathfrak{g},K)} -cohomological cusp forms of GSp 4 ( 𝔸 F ) {\mathrm{GSp_{4}}(\mathbb{A}_{F})} all qualify to be of the above type – providing a large source of examples. We expect that these period relations for GSp 4 ( 𝔸 F ) {\mathrm{GSp_{4}}(\mathbb{A}_{F})} will allow a conceptual, fine treatment of rationality relations of special values of the spin L-function, which we hope to report on in Part II of this paper.
- Published
- 2017
88. Comparison of ψ-porous topologies
- Author
-
Ewa Łazarow, Małgorzata Turowska, and Krystian Rychert
- Subjects
General Mathematics ,Network topology ,Topology ,Porosity ,Mathematics - Abstract
The purpose of this paper is to study the notion of a ψ-porosity point and ψ-porosity topology, generated by it analogously to the porosity topology on the real line. The paper includes a necessary and sufficient conditions under which two ψ-porous topologies generated by two functions ψ 1 and ψ 2 are equal. The condition is formulated in terms of the behavior of two sequences of sets A k = { x ∈ ( 0 , ∞ ) : ψ 1 ( x ) < 1 k ψ 2 ( x ) } and B k = { x ∈ ( 0 , ∞ ) : ψ 2 ( x ) < 1 k ψ 1 ( x ) } . $\begin{array}{} A_k=\{x\in(0,\infty)\colon\psi_1(x) \lt \frac{1}{k}\psi_2(x)\} \text{ and } B_k=\{x\in(0,\infty)\colon\psi_2(x) \lt \frac{1}{k}\psi_1(x)\}. \end{array}$
- Published
- 2017
89. Radiation of Heat in an Insulating Vacuum Layer
- Author
-
Mária Minárová
- Subjects
Thermal radiation ,General Mathematics ,021105 building & construction ,0211 other engineering and technologies ,02 engineering and technology ,Composite material ,021001 nanoscience & nanotechnology ,0210 nano-technology ,Layer (electronics) ,Mathematics - Abstract
The paper is motivated by the previous research concerning the heat transfer in a heat accumulation device. The device had been explored, built up and tested with the aim of utilization of cheap solar energy and its storage. In this heat storage system, a vacuum-like gap between two concentric containers acts as an insulating layer, radiation being the predominant heat transfer type in the gap. The better knowledge and understanding of the heat exchange by radiation, the more effectiveness of the insulation of the layer can be reached. Heat transfer by radiation is explored in the paper, mathematical model is set up, the algorithm of non-linear transient computation is introduced, and some illustrative results of this computation are performed.
- Published
- 2017
90. The geometry of two-valued subsets of Lp -spaces
- Author
-
Anthony Weston
- Subjects
Measurable function ,General Mathematics ,010102 general mathematics ,Basis (universal algebra) ,Type (model theory) ,Space (mathematics) ,01 natural sciences ,Measure (mathematics) ,Omega ,010101 applied mathematics ,Combinatorics ,Essential range ,Isometry ,0101 mathematics ,Mathematics - Abstract
Let 𝓜(Ω, μ) denote the algebra of all scalar-valued measurable functions on a measure space (Ω, μ). Let B ⊂ 𝓜(Ω, μ) be a set of finitely supported measurable functions such that the essential range of each f ∈ B is a subset of {0,1}. The main result of this paper shows that for any p ∈ (0, ∞), B has strict p-negative type when viewed as a metric subspace of L p (Ω, μ) if and only if B is an affinely independent subset of 𝓜(Ω, μ) (when 𝓜(Ω, μ) is considered as a real vector space). It follows that every two-valued (Schauder) basis of L p (Ω, μ) has strict p-negative type. For instance, for each p ∈ (0, ∞), the system of Walsh functions in L p [0,1] is seen to have strict p-negative type. The techniques developed in this paper also provide a systematic way to construct, for any p ∈ (2, ∞), subsets of L p (Ω, μ) that have p-negative type but not q-negative type for any q > p. Such sets preclude the existence of certain types of isometry into L p -spaces.
- Published
- 2017
91. Binomials transformation formulae for scaled Fibonacci numbers
- Author
-
Edyta Hetmaniok, Roman Wituła, and Bożena Piątek
- Subjects
δ-lucas numbers ,Fibonacci number ,General Mathematics ,llb83 ,010102 general mathematics ,binomial transformation ,0102 computer and information sciences ,Pisano period ,llb39 ,01 natural sciences ,Combinatorics ,Transformation (function) ,010201 computation theory & mathematics ,Fibonacci polynomials ,QA1-939 ,0101 mathematics ,δ-fibonacci numbers ,Mathematics - Abstract
The aim of the paper is to present the binomial transformation formulae of Fibonacci numbers scaled by complex multipliers. Many of these new and nontrivial relations follow from the fundamental properties of the so-called delta-Fibonacci numbers defined by Wituła and Słota. The paper contains some original relations connecting the values of delta-Fibonacci numbers with the respective values of Chebyshev polynomials of the first and second kind.
- Published
- 2017
92. Donaldson–Thomas invariants versus intersection cohomology of quiver moduli
- Author
-
Markus Reineke and Sven Meinhardt
- Subjects
Pure mathematics ,Mathematics::Algebraic Geometry ,Conjecture ,Intersection ,Intersection homology ,Applied Mathematics ,General Mathematics ,Quiver ,Closure (topology) ,Invariant (mathematics) ,Moduli ,Moduli space ,Mathematics - Abstract
The main result of this paper is the statement that the Hodge theoretic Donaldson–Thomas invariant for a quiver with zero potential and a generic stability condition agrees with the compactly supported intersection cohomology of the closure of the stable locus inside the associated coarse moduli space of semistable quiver representations. In fact, we prove an even stronger result relating the Donaldson–Thomas “function” to the intersection complex. The proof of our main result relies on a relative version of the integrality conjecture in Donaldson–Thomas theory. This will be the topic of the second part of the paper, where the relative integrality conjecture will be proven in the motivic context.
- Published
- 2017
93. Non-autonomous Eigenvalue Problems with Variable (p 1,p 2)-Growth
- Author
-
Nejmeddine Chorfi, Souhail Chebbi, Vicenţiu D. Rădulescu, and Sami Baraket
- Subjects
010101 applied mathematics ,Variable exponent ,General Mathematics ,010102 general mathematics ,Continuous spectrum ,Applied mathematics ,Statistical and Nonlinear Physics ,0101 mathematics ,01 natural sciences ,Eigenvalues and eigenvectors ,Variable (mathematics) ,Mathematics - Abstract
We are concerned with the study of a class of non-autonomous eigenvalue problems driven by two non-homogeneous differential operators with variable ( p 1 , p 2 ) {(p_{1},p_{2})} -growth. The main result of this paper establishes the existence of a continuous spectrum consisting in an unbounded interval and the nonexistence of eigenvalues in a neighbourhood of the origin. The abstract results of this paper are described by two Rayleigh-type quotients and the proofs rely on variational arguments.
- Published
- 2017
94. Fejér-type inequalities (II)
- Author
-
Shiow-Ru Hwang, Kuei-Lin Tseng, and Sever S Dragomir
- Subjects
010101 applied mathematics ,Pure mathematics ,Inequality ,General Mathematics ,media_common.quotation_subject ,010102 general mathematics ,0101 mathematics ,Type (model theory) ,01 natural sciences ,Mathematics ,media_common - Abstract
In this paper, we establish some Fejér-type inequalities for convex functions. They complement the results from the previous recent paper [Dragomir, S. S.—Milošević, D. S.——Sándor, J.: On some refinements of Hadamard’s inequalities and applications, Univ. Belgrad. Publ. Elek. Fak. Sci. Math. 4 (1993), 3–10].
- Published
- 2017
95. Law of inertia for the factorization of cubic polynomials – the case of primes 2 and 3
- Author
-
Jiří Klaška and Ladislav Skula
- Subjects
Discrete mathematics ,General Mathematics ,010102 general mathematics ,Galois theory ,Factorization of polynomials over finite fields ,0102 computer and information sciences ,16. Peace & justice ,01 natural sciences ,Prime (order theory) ,Combinatorics ,Discriminant ,Factorization ,Integer ,010201 computation theory & mathematics ,Factorization of polynomials ,0101 mathematics ,Monic polynomial ,Mathematics - Abstract
Let D ∈ ℤ and let C D be the set of all monic cubic polynomials x 3 + ax 2 + bx + c ∈ ℤ[x] with the discriminant equal to D. Along the line of our preceding papers, the following Theorem has been proved: If D is square-free and 3 ∤ h(−3D) where h(−3D) is the class number of Q ( − 3 D ) , $\mathbb Q(\sqrt {-3D}),$ then all polynomials in C D have the same type of factorization over the Galois field 𝔽 p where p is a prime, p > 3. In this paper, we prove the validity of the above implication also for primes 2 and 3.
- Published
- 2017
96. Coupled Versus Uncoupled Blow-Up Rates in Cooperative n-Species Logistic Systems
- Author
-
Julián López-Gómez and Luis Maire
- Subjects
010101 applied mathematics ,General Mathematics ,010102 general mathematics ,Applied mathematics ,Statistical and Nonlinear Physics ,0101 mathematics ,01 natural sciences ,Mathematics - Abstract
This paper ascertains the exact boundary blow-up rates of the large positive solutions of a class of cooperative logistic systems involving n species in a general domain of ℝ N {\mathbb{R}^{N}} of class 𝒞 2 + ν {\mathcal{C}^{2+\nu}} , 0 < ν < 1 {0 . The problem models a population divided in groups whose individuals compete with those of the same group, while simultaneously they cooperate with the members of the remaining groups. Our main result provides with the exact blow-up rates along the edges of Ω from the values of the blow-up rates of the underlying uncoupled system. Rather astonishingly, these blow-up rates are independent of the strength of the cooperative effects, which play a secondary role in the analysis carried out in this paper. No previous result of this nature is available in the specialized literature for more than n = 2 {n=2} species.
- Published
- 2017
97. Piecewise synergetic systems and applications in biochemical systems theory
- Author
-
Arkadi Ponossov, Anna Machina, and Valeria Tafintseva
- Subjects
0301 basic medicine ,03 medical and health sciences ,030104 developmental biology ,Theoretical computer science ,General Mathematics ,Piecewise ,Biochemical systems theory ,Mathematics - Abstract
We study piecewise synergetic systems originating from Biochemical Systems Theory. In the first part of the paper, the emphasis is put on practical calculations with such systems. We consider four examples: calculation of trajectories and steady states, solution of an optimization problem and a method of estimation of parameters (kinetic orders), all examples being biologically motivated. In the second part of the paper, we study convergence of solutions, in particularly, steady states, of a sequence of piecewise synergetic systems approximating an arbitrary compartment model. This convergence analysis is then applied to the optimization problem and the method of estimating sensitivities (kinetic orders) in a generic compartment model. In this paper we put forward arguments for the importance of the theoretical and numerical analysis of piecewise synergetic systems.
- Published
- 2016
98. Impulsive differential inclusions via variational method
- Author
-
Abdelghani Ouahab, Mouffak Benchohra, and Juan J. Nieto
- Subjects
Variational method ,Differential inclusion ,General Mathematics ,010102 general mathematics ,0502 economics and business ,05 social sciences ,Mathematical analysis ,050207 economics ,0101 mathematics ,01 natural sciences ,Mathematics - Abstract
In this paper, we establish several results about the existence of second-order impulsive differential inclusion with periodic conditions. By using critical point theory, several new existence results are obtained. We also provide an example in order to illustrate the main abstract results of this paper.
- Published
- 2016
99. Existence and uniqueness of best proximity points under rational contractivity conditions
- Author
-
Erdal Karapınar, Antonio-Francisco Roldán-López-de-Hierro, and Kishin Sadarangani
- Subjects
010101 applied mathematics ,General Mathematics ,010102 general mathematics ,Mathematical analysis ,Applied mathematics ,Uniqueness ,0101 mathematics ,01 natural sciences ,Mathematics - Abstract
The main aim of this paper is to present some theorems in order to guarantee existence and uniqueness of best proximity points under rational contractivity conditions using very general test functions. To illustrate the variety of possible test functions, we include some examples of pairs of functions which are included in innovative papers published in the last years. As a consequence, we prove that our results unify and extend some recent results in this field.
- Published
- 2016
100. Essential regularity of the model space for the Weil–Petersson metric
- Author
-
Georgios Daskalopoulos and Chikako Mese
- Subjects
Algebra ,Applied Mathematics ,General Mathematics ,010102 general mathematics ,0103 physical sciences ,Metric (mathematics) ,Mathematical analysis ,ComputingMethodologies_DOCUMENTANDTEXTPROCESSING ,010307 mathematical physics ,0101 mathematics ,Space (mathematics) ,01 natural sciences ,Mathematics - Abstract
This is the second in a series of papers ([7] and [6] are the others) that studies the behavior of harmonic maps into the Weil–Petersson completion 𝒯 ¯ {\overline{\mathcal{T}}} of Teichmüller space. The boundary of 𝒯 ¯ {\overline{\mathcal{T}}} is stratified by lower-dimensional Teichmüller spaces and the normal space to each stratum is a product of copies of a singular space 𝐇 ¯ {\overline{\bf H}} called the model space. The significance of 𝐇 ¯ {\overline{\bf H}} is that it captures the singular behavior of the Weil–Petersson geometry of 𝒯 ¯ {\overline{\mathcal{T}}} . The main result of the paper is that certain subsets of 𝐇 ¯ {\overline{\bf H}} are essentially regular in the sense that harmonic maps to those spaces admit uniform approximation by affine functions. This is a modified version of the notion of essential regularity introduced by Gromov–Schoen in [12] for maps into Euclidean buildings and is one of the key ingredients in proving superrigidity. In the process, we introduce new coordinates on 𝐇 ¯ {\overline{\bf H}} and estimate the metric and its derivatives with respect to the new coordinates. These results form the technical core for studying the analytic behavior of harmonic maps into the completion of Teichmüller space and are utilized in our subsequent paper [6], where we prove the holomorphic rigidity of the Teichmüller space and several rigidity results for the mapping class group.
- Published
- 2016
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