关于Banach空间中渐近非扩张型半群的不动点与渐近行为

Let X be a Banach space with a weakly continuous duality map Jφ,C a non-empty weakly compact convex subset of X, and T:(T(t):t∈S} an asymptotically nonexpansive type semigroup on C. In this paper, the inequality K∩F(T)≠0 is characterized, where K is a subset of C and F(T) is the set of all common fixed points of T. Furthermore, it is shown that an almost-orbit {u(t):t∈S} of T converges weakly to a point in F(T) if and only if {u(t):t∈S}is weakly asymptotically regular.     

一些超空间的非双Lipschitz 齐次性

A metric space(X, d) is called bi-Lipschitz homogeneous if for any points x, y ∈ X,there exists a self-homeomorphism h of X such that both h and h-1are Lipschitz and h(x) = y.Let 2(X,d)denote the family of all non-empty compact subsets of metric space(X, d) with the Hausdorff metric. In 1985, Hohti proved that 2([0,1],d)is not bi-Lipschitz homogeneous, where d is the standard metric on [0, 1]. We extend this result in two aspects. One is that 2([0,1],e)is not bi-Lipschitz homogeneous for an admissible metric e satisfying some conditions. Another is that 2(X,d)is not bi-Lipschitz homogeneous if(X, d) has a nonempty open subspace which is isometric to an open subspace of m-dimensional Euclidean space Rm.     

Delay-Dependent Exponential Stability for Nonlinear Reaction-Diffusion Uncertain Cohen-Grossberg Neural Networks with Partially Known Transition Rates via Hardy-Poincaré Inequality

In this paper, stochastic global exponential stability criteria for delayed impulsive Markovian jumping reaction-diffusion Cohen-Grossberg neural networks(CGNNs for short) are obtained by using a novel Lyapunov-Krasovskii functional approach, linear matrix inequalities(LMIs for short) technique, It formula, Poincar′e inequality and Hardy-Poincaré inequality, where the CGNNs involve uncertain parameters, partially unknown Markovian transition rates, and even nonlinear p-Laplace diffusion(p 1). It is worth mentioning that ellipsoid domains in Rm(m ≥ 3) can be considered in numerical simulations for the first time owing to the synthetic applications of Poincar′e inequality and Hardy-Poincar′e inequality. Moreover, the simulation numerical results show that even the corollaries of the obtained results are more feasible and effective than the main results of some recent related literatures in view of significant improvement in the allowable upper bounds of delays.     

Fixed Points and Asymptotic Behavior for Asymptotically Nonexpansive Type Semigroups in Banach Spaces

Let X be a Banach space with a weakly continuous duality map Jψ, C a non-empty weakly compact convex subset of X, and T = (T(t) : t ∈ S} an asymptotically nonexpansive type semigroup on C. In this paper, the inequality K ∩ F(T) ≠ (?) is characterized, where K is a subset of C and F(T) is the set of all common fixed points of T. Furthermore, it is shown that an almost-orbit     

Stability of <Emphasis Type="Italic">C</Emphasis>-regularized Semigroups

Let T = (T(t))t≥0 be a bounded C-regularized semigroup generated by A on a Banach space X and R(C) be dense in X. We show that if there is a dense subspace Y of X such that for every x ∈ Y, σu(A, Cx), the set of all points λ ∈ iR to which (λ - A)^-1 Cx can not be extended holomorphically, is at most countable and σr(A) N iR = Ф, then T is stable. A stability result for the case of R(C) being non-dense is also given. Our results generalize the work on the stability of strongly continuous senfigroups.     

Variational Principle for Topological Pressure on Subsets of Free Semigroup Actions

We investigate the relations between Pesin–Pitskel topological pressure on an arbitrary subset and measure-theoretic pressure of Borel probability measures for finitely generated semigroup actions. Let(X, G) be a system, where X is a compact metric space and G is a finite family of continuous maps on X. Given a continuous function f on X, we define Pesin–Pitskel topological pressure P_G(Z, f)for any subset Z ■ X and measure-theoretical pressure P_(μ,G)(X, f) for any μ∈ M(X), where M(X)denotes the set of all Borel probability measures on X. For any non-empty compact subset Z of X, we show that P_G(Z, f) = sup{P_(μ,G)(X, f) : μ∈ M(X), μ(Z) = 1}.     

Global-in-time Uniform Convergence for Linear Hyperbolic-Parabolic Singular Perturbations

We consider the Cauchy problem εu^″ε ＋ δu′ε ＋ Auε = 0, uε（0） = uo, u′ε（0） = ul, where ε 〉 0, δ 〉 0, H is a Hilbert space, and A is a self-adjoint linear non-negative operator on H with dense domain D（A）. We study the convergence of （uε） to the solution of the limit problem ,δu＇ ＋ Au = 0, u（0） = u0. For initial data （u0, u1） ∈ D（A1/2）× H, we prove global-in-time convergence with respect to strong topologies. Moreover, we estimate the convergence rate in the case where （u0, u1）∈ D（A3/2） ∈ D（A1/2）, and we show that this regularity requirement is sharp for our estimates. We give also an upper bound for ｜u′ε（t）｜ which does not depend on ε.     

HLDER CONTINUOUS SOLUTIONS FOR SECOND ORDER INTEGRO-DIFFERENTIAL EQUATIONS IN BANACH SPACES

We study Hlder continuous solutions for the second order integro-differential equations with infinite delay (P1): u′′(t)+cu′(t)+∫t-∞β(t-s)u′(s)ds+∫t-∞γ(t-s)u(s)ds = Au(t)-∫t-∞δ(t-s)Au(s)ds + f(t)on the line R, where 0 < α < 1, A is a closed operator in a complex Banach space X, c ∈ C is a constant, f ∈ C~α(R,X) and β,γ,δ∈L~1(R+).Under suitable assumptions on the kernels β, γ and δ, we completely characterize the C~α- well-posedness of (P_1) by using operator-valued C~α-Fourier multipliers.     

Translative containment measure and symmetric mixed isohomothetic inequalities

We first investigate the translative containment measure for convex domain K0 to contain, or to be contained in, the homothetic copy of another convex domain K1, i.e., given two convex domains K0, K1 of areas A0, A1, respectively, in the Euclidean plane R2, is there a translation T so that t(T K1)  K0 or t(T K1) ? K0 for t 0? Via the translative kinematic formulas of Poincar′e and Blaschke in integral geometry,we estimate the symmetric mixed isohomothetic deficit σ2(K0, K1) ≡ A201- A0A1, where A01 is the mixed area of K0 and K1. We obtain a sufficient condition for K0 to contain, or to be contained in, t(T K1). We obtain some Bonnesen-style symmetric mixed isohomothetic inequalities and reverse Bonnesen-style symmetric mixed isohomothetic inequalities. These symmetric mixed isohomothetic inequalities obtained are known as Bonnesen-style isopermetric inequalities and reverse Bonnesen-style isopermetric inequalities if one of domains is a disc. As direct consequences, we obtain some inequalities that strengthen the known Minkowski inequality for mixed areas and the Bonnesen-Blaschke-Flanders inequality.     

Hölder continuous solutions for second order integro-differential equations in banach spaces

We study Hlder continuous solutions for the second order integro-differential equations with infinite delay （P1）: u′′（t）+cu′（t）+∫t-∞β（t-s）u′（s）ds+∫t-∞γ（t-s）u（s）ds = Au（t）-∫t-∞δ（t-s）Au（s）ds + f（t）on the line R, where 0 < α < 1, A is a closed operator in a complex Banach space X, c ∈ C is a constant, f ∈ C^α（R,X） and β,γ,δ∈L¹（R+）.Under suitable assumptions on the kernels β, γ and δ, we completely characterize the C^α- well-posedness of （P₁） by using operator-valued C^α-Fourier multipliers.     

Maximal regularity of second order delay equations in Banach spaces

We give necessary and sufficient conditions of Lp-maximal regularity(resp.B sp ,q-maximal regularity or F sp ,q-maximal regularity) for the second order delay equations:u″(t)=Au(t) + Gu't + F u t + f(t), t ∈ [0, 2π] with periodic boundary conditions u(0)=u(2π), u′(0)=u′(2π), where A is a closed operator in a Banach space X,F and G are delay operators on Lp([-2π, 0];X)(resp.Bsp ,q([2π, 0];X) or Fsp,q([-2π, 0;X])).     

NUMERICALLY SOLVING PERIODICALLY PERTURBED CONSERVATIVE SYSTEMS BY PARAMETER EMBEDDING METHODS

1　IntroductionConsider the system of differential equationsTu≡ u"+ F( t,u) =0 ( 1 )where F:R×Rn→Rnis a continuos function of2 π-period with respect to tand F( t,· )∈ C1( Rn,Rn) has a symmetric derivative for all t∈R and allξ∈Rn.When the system is of the formu"+ grad G( u) =e( t) ( 2 )where G∈C2 ( Rn,R) ,e:R→Rncontinuousand2 π-periodic.Equation( 2 ) can be interpreted asthe Newtonian equation ofmotion ofa mechanicalsystem subjectto conservative internal forcesand periodic e…     

Triple positive periodic solutions of nonlinear singular second-order boundary value problems

This paper studies the positive solutions of the nonlinear second-order periodic boundary value problem u″(t) + λ(t)u(t) = f(t,u(t)),a.e.t ∈ [0,2π],u(0) = u(2π),u′(0) = u′(2π),where f(t,u) is a local Carath′eodory function.This shows that the problem is singular with respect to both the time variable t and space variable u.By applying the Leggett–Williams and Krasnosel'skii fixed point theorems on cones,an existence theorem of triple positive solutions is established.In order to use these theorems,the exact a priori estimations for the bound of solution are given,and some proper height functions are introduced by the estimations.     

Jackson’s theorem in Q_p spaces

A Jackson type inequality in Q p spaces is established, i.e., for any f (z) = Σ∞ j=0 ajzj ∈ Qp , 0≤p ∞, a 1, and k-1 ∈ N,where ω(1/k, f, Q p ) is the modulus of continuity in Q p spaces and C(a) is an absolute constant depending only on the parameter a.     

VORTEX DYNAMICS OF THE ANISOTROPIC GINZBURG-LANDAU EQUATION

In this article, using coordinate transformation and Gronwall inequality, we study the vortex motion law of the anisotropic Ginzburg-Landau equation in a smooth bounded domain Ω  R2, that is, ■tuε = 2Σ/j,k=1 (ajkj■xjkuε)xj + b(x)(1-ε|ε|2)uε/2u, x ∈Ω, and conclude that each vortex bj(t) (j=1, 2,···, N) satisfies dbdjt(t)= -(a1k(bj(t)b)■(xk))a(a (bj(t)), a2k(bj (t))/xk a(bj (t)) a(bj (t)) , where a(x) =(a11a22-a122(1/2)). We prove that all the vortices are pinned together to the critical points of a(x). Furthermore, we prove that these critical points can not be the maximum points.     

STOCHASTIC HEAT EQUATION WITH FRACTIONAL LAPLACIAN AND FRACTIONAL NOISE:EXISTENCE OF THE SOLUTION AND ANALYSIS OF ITS DENSITY

In this paper we study a fractional stochastic heat equation on R~d(d≥1) with additive noise ?/?t u(t,x) = Dα/δu(t,x) + b(u(t,x)) +W~H(t,x) where D α/δ is a nonlocal fractional differential operator and W~H is a Gaussian-colored noise. We show the existence and the uniqueness of the mild solution for this equation. In addition,in the case of space dimension d=1,we prove the existence of the density for this solution and we establish lower and upper Gaussian bounds for the density by Malliavin calculus.     

Effective Reducibility of a Class of Linear Differential Equations with Quasiperiodic Coefficients

In this paper we consider the effective reducibility of the following linear differentialequation: x = (A ∈Q(t,∈))x, |∈| ≤ ∈0, where A is a constant matrix, Q(t,e) is quasiperiodic in t, and e is a small perturbation parameter. We prove that if the eigenvalues of A and the basic frequencies of Q satisfy some non-resonant conditions, the linear differential equation can be reduced to y = (A^*(∈) R^*(t, ∈))y, |∈| ≤ ∈o, where R^* is exponentially small in ∈.     

Delay-Dependent Exponential Stability for Nonlinear Reaction-Diffusion Uncertain Cohen-Grossberg Neural Networks with Partially Known Transition Rates via Hardy-Poincar′e Inequality

In this paper, stochastic global exponential stability criteria for delayed impulsive Markovian jumping reaction-diffusion Cohen-Grossberg neural networks (CGNNs for short) are obtained by using a novel Lyapunov-Krasovskii functional approach, linear matrix inequalities (LMIs for short) technique, It? formula, Poincare inequality and Hardy-Poincare inequality, where the CGNNs involve uncertain parameters, partially unknown Markovian transition rates, and even nonlinear p-Laplace diffusion (p > 1). It is worth mentioning that ellipsoid domains in $R^m$ (m ≥ 3) can be considered in numerical simulations for the first time owing to the synthetic applications of Poincar′e inequality and Hardy-Poincar′e inequality. Moreover, the simulation numerical results show that even the corollaries of the obtained results are more feasible and effective than the main results of some recent related literatures in view of significant improvement in the allowable upper bounds of delays.     

REGULARITY OF SUPERMARTINCALES INDEXED BY A LATTICE-ORDERED SET

Let X= {x_t; t∈T} be a supermartingale (resp. martingale) defined on a probability space (Ω,(?), P) with respect to (?), where (?)={(?)_t; t∈T} is nondecreasing family of sub-σ-algebras of (?). It is well known that (see Theorem 2.27 in [1] ) when T=(?)= {0, 1, …,∞}, the supermartingale (resp. martingale) X possesses the (?)-regularity, i.e., for every τ,σ∈(?) such that τ≤σ,     

Existence of best simultaneous approximations in L_p(S, Σ, X) without the RNP assumption

Let(S, Σ, μ) be a complete positive σ-finite measure space and let X be a Banach space. We consider the simultaneous proximinality problem in Lp(S, Σ, X) for 1 p +∞. We establish some N-simultaneous proximinality results of Lp(S, Σ0, Y) in Lp(S, Σ, X) without the Radon-Nikody′m property(RNP) assumptions on the space span Y and its dual span Y*, where Σ0is a sub-σ-algebra of Σ and Y a nonempty locally weakly compact closed convex subset of X. In particular, we completely solve one open problem and partially solve another one in Luo et al.(2011).