共查询到20条相似文献,搜索用时 31 毫秒
1.
M.C. Câmara 《Journal of Mathematical Analysis and Applications》2010,367(2):416-640
A factorability criterion is obtained constructively, and the respective factorization obtained explicitly, for 2×2 triangular almost periodic matrix functions of the form . Here f=c−1e−α−c0+c1eβ, eμ(x):=eiμx, cj are non-zero constants and 0<α,β, α+β<λ?α+β+max{α,β} with α/β being irrational. Note that the factorization problem, even for triangular matrix functions as above with an arbitrary trinomial f, is open. The result obtained is yet another step towards its solution. 相似文献
2.
M.A. Bastos 《Journal of Mathematical Analysis and Applications》2011,376(2):625-640
Using an abbreviation eμ to denote the function eiμx on the real line R, let , where f is a linear combination of the functions eα, eβ, eα−λ, eβ−λ with some . The criterion for G to admit a canonical factorization was established recently by Avdonin, Bulanova and Moran (2007) [1]. We give an alternative approach to the matter, proving the existence (when it does take place) via deriving explicit factorization formulas. The non-existence of the canonical factorization in the remaining cases then follows from the continuity property of the geometric mean. 相似文献
3.
In this paper, we present a theorem on the almost periodic solutions of second-order neutral equations with piecewise constant arguments of the form
where [⋅] denotes the greatest integer function, p,q (|p|>1 or p=−1) are nonzero constants, and f(t) is almost periodic. 相似文献
(x(t)+px(t−1))″=qx([t])+f(t),
4.
We analyse almost periodic homogeneous linear difference systems whose coefficient matrices belong to the so-called transformable groups. We introduce the notion of weakly transformable groups and we use this notion to obtain generalizations of known results about non-almost periodic solutions of considered systems. 相似文献
5.
Zuosheng Hu Angelo B. Mingarelli 《Proceedings of the American Mathematical Society》2004,132(2):417-428
We obtain sufficient conditions for the existence of almost periodic solutions of almost periodic linear differential equations thereby extending Favard's classical theorem. These results are meant to complement previous results of the authors who have shown by means of a counterexample that the boundedness of all solutions is not, by itself, sufficient to guarantee the existence of an almost periodic solution to a linear almost periodic differential equation.
6.
Da Xiong Piao 《数学学报(英文版)》2002,18(2):263-276
In this paper, we study the existence of almost periodic solutions of neutral differential difference equations with piecewise
constant arguments via difference equation methods.
Received February 18, 2000, Accepted September 30, 2000. 相似文献
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8.
Jaeyoung Chung Soon-Yeong Chung Dohan Kim Hee Jung Kim 《Proceedings of the American Mathematical Society》2001,129(3):731-738
We characterize the almost periodic hyperfunctions by showing that the following statements are equivalent for any bounded hyperfunction . (i) is almost periodic. (ii) for every . (iii) There are two functions and an infinite order differential operator such that (iv) The Gauss transform of is almost periodic for every 0$">. Here is the space of almost periodic continuous functions, is the Sato space of test functions for the Fourier hyperfunctions, and is the heat kernel. This generalizes the result of Schwartz on almost periodic distributions and that of Cioranescu on almost periodic (non-quasianalytic) ultradistributions to the case of hyperfunctions.
9.
A maximum principle is proved for the weak solutions of the telegraph equation in space dimension three utt−Δxu+cut+λu=f(t,x), when c>0, λ∈(0,c2/4] and (Theorem 1). The result is extended to a solution and a forcing belonging to a suitable space of bounded measures (Theorem 2). Those results provide a method of upper and lower solutions for the semilinear equation utt−Δxu+cut=F(t,x,u). Also, they can be employed in the study of almost periodic solutions of the forced sine-Gordon equation. A counterexample for the maximum principle in dimension four is given. 相似文献
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11.
Vladimir Pestov 《Topology and its Applications》1998,90(1-3):223-225
Answering a question first explicitly stated by de Vries in 1993, we observe that for an arbitrary topological dynamical system the property of being an almost periodic point does not depend on the topology of the acting group. In other words, the traditional distinction made between the notions of an almost periodic point and of a discretely almost periodic point is unnecessary. 相似文献
12.
1Introduction:Recellt,lyIt.SchlniltandJa,nJ(lsit.Ward,JR.[l]developedamclfllo(1forestablishillgtheexistellceofalmostperiodicsolutionstonolllillcal'secorl'1order相似文献
13.
Hui-Sheng Ding Jin Liang Gaston M. N’Guérékata Ti-Jun Xiao 《Nonlinear Analysis: Theory, Methods & Applications》2007
This paper is concerned with pseudo-almost periodicity of the solutions to the nonautonomous evolution equation with delay u′(t)=A(t)u(t)+f(t,u(t−h)). Some sufficient conditions which ensure the existence and uniqueness of pseudo-almost periodic mild solutions to the evolution equation with delay are given. An example is shown to illustrate our results. 相似文献
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15.
Gani Stamov 《Applicable analysis》2013,92(1-2):45-56
Sufficirnt condition for the existence of almost periodic solutions of forced perturbed systems of impulsive differential equations with impulsive effect at fixed Moments are considered. 相似文献
16.
Leiba Rodman Ilya M. Spitkovsky Hugo J. Woerdeman 《Proceedings of the American Mathematical Society》2002,130(5):1365-1370
We consider Toeplitz operators with symbols that are almost periodic matrix functions of several variables. It is shown that under certain conditions on the group generated by the Fourier support of the symbol, a Toeplitz operator is Fredholm if and only if it is invertible.
17.
L.I. Danilov 《Journal of Mathematical Analysis and Applications》2006,316(1):110-127
We prove that Weyl almost periodic multivalued maps R∋t→F(t)∈clU have Weyl almost periodic selections, where clU is the collection of non-empty closed sets of a complete metric space U. 相似文献
18.
Yihong Song 《Journal of Mathematical Analysis and Applications》2006,314(1):174-194
For discrete Volterra equations with or without delay, we obtain several results concerning almost periodic solutions and asymptotically almost periodic solutions under certain conditions. We also investigate the relations among solutions of equations discussed and give an example to illustrate our results. 相似文献
19.
ONALMOSTPERIODICSOLUTIONSFORACLASSOFFUNCTIONALDIFFERENTIALEQUATIONS¥WangZhen(王震)&LuoYi(骆毅)(AnhuiUniversity)Abstract:Thispaper... 相似文献
20.
A note on sensitivity of semigroup actions 总被引:1,自引:0,他引:1
It is well known that for a transitive dynamical system (X,f) sensitivity to initial conditions follows from the assumption that the periodic points are dense. This was done by several
authors: Banks, Brooks, Cairns, Davis and Stacey (Am. Math. Mon. 99, 332–334, 1992), Silverman (Rocky Mt. J. Math. 22, 353–375, 1992) and Glasner and Weiss (Nonlinearity 6, 1067–1075, 1993). In the latter article Glasner and Weiss established a stronger result (for compact metric systems) which implies that a
transitive non-minimal compact metric system (X,f) with dense set of almost periodic points is sensitive. This is true also for group actions as was proved in the book of
Glasner (Ergodic Theory via Joinings, 2003).
Our aim is to generalize these results in the frame of a unified approach for a wide class of topological semigroup actions
including one-parameter semigroup actions on Polish spaces. 相似文献