Banach空间中线性算子方程的约束极值解

设X,Y与Z为Banach空间L∈L(X,Z),T∈L(X,Y)为线性算子.运用线性算子的度量广义逆概念,在L(x)=y的极值解集合中,给出T(x)=h的约束极值解的精确刻画.     

紧框架的一个注记

假设Φ(x)∈L^2(R)且具有紧支集。令V=span^—{Φ(x—k)|k∈Z}。在这篇短文中，我们证明：如果{Φ(x—k)|k∈Z}是V的界为1的紧框架，那么{Φ(x—k)|k∈Z}一定是V的一个标准正交基。     

关于序集碰撞数问题深度贪心算法的最优性

§1.引言称P=(X,≤)是一个序集是指,X是一个集合,“≤”是X上的一个二元关系(叫做小于等于),它满足:(1)自反性,(x≤x,x∈X),(2)传递性(x≤y,y≤z■x≤z)和(3)反对称性x≤y,y≤x,■x=y)。本文只讨论有限序集。用|X|或|P|表示序集P=(X,≤)所含有的元素个数,用x∈P或x∈X表示x是P的元素。对任一序集Q,我们也用相同的字母Q表示它的基本集。在序集P中,如果x≤y,则我们也用x≤y(P),y≥x及y≥x(P)来表示这一关系。     

非自反实Banach空间中的广义共同远达点问题的适定性

设C是实Banach空间X中有界闭凸子集且O是C的内点,G是X中非空有界闭的相对弱紧子集.记K(X)为X的非空紧凸子集并赋Hausdorff距离.称广义共同远达点问题maxc(A,G)是适定的是指它有唯一解(x0,z0)且它的每个极大化序列均强收敛到(x0,z0).在C是严格凸和Kadec的假定下,我们运用不同于DeBlasi,MyjalandPapini和Li等人的方法证明了集{A∈K(X);maxc(A,G)是适定的}含有K(X)中稠Gδ集,这本质地推广和延拓了包括DeBlasi,MyjakandPapini和Li等人在内的近期相应结果.     

线性拓扑空间中太阳集的若干逼近性质

1958年Efimov-steckin引入“太阳集”(sun)概念.Brosowski、Amir-Deutsch,Brosowski-Deutsch广泛研究了它的性质.太阳集是凸集的弱化.在赋范空间中的逼近理论有重要作用.因为在逼近问题上,这种集合往往可以取代凸集的作用.这个词的意思是:所谓G是个太阳集,乃是对于G以外任一元素x G.若g_0∈G是对x的一切G中元的一个佳逼元(如果存在),则对于从g_0引通过x的射线的一切元素说,g_0也是其一个佳逼元.在赋范空间中,这里所研究佳逼性,就是范数||g-x||当g遍历G而到达最小值的意思.现在扩充概念到线性拓扑空间X中.设给定了一个实值泛函数φ(x),规定为绝齐性、次加性的.即     

一个极值问题

设X、Z是两线性赋范空间,Y是巴拿赫空间,映射:X→Y,说在x_0∑X处有Frechet导数l,即有界线性算子l:X→Y,满足||(x_0+εx)-x_0-εlx||_Y=o(ε),x∈X,ε→0。又连续线性算子Г:X→Z,Ω是Z中的凸集,记U={x∈X|Г(x)∈Ω},U_0={x∈X|Г(x)=0}。设F是Y上的连续凸泛函,考虑极值问题:     

Banach 空间中非线性最佳逼近的广义强唯一性

设X是一致凸空间,G为X中太阳集,R．Smarzewski[1]证明了g∈G对x∈的最佳逼近具有广义强唯一性,本文讨论其逆,在最佳逼近是广义强唯一的条件下,研究了空间的凸性和逼近集的太阳性．     

具Hardy-Sobolev临界指数的奇异椭圆方程多解的存在性

运用变分方法研究了下面问题-Δpu=μupx(s)s-2u f(x,u),x∈Ω,u=0,x∈Ω,多重解的存在性,其中Ω是一个具有光滑边界的有界区域.     

广义Lévy单的样本轨道性质

设X(t)是下指数为α取值于R~d的N参数广义Lévy单,■={(s,t]=∏(s_i,t_i],s_i＜t_i},E(x,Q)={t∈Q:X(t)=x},Q∈■,是X在点x处的水平集,X(Q)={x:■t∈Q,使得X(t)=x}为X在Q上的像集．本文探讨了X(t)局部时存在性及其增量的大小．同时,也得到了水平集E(x,Q)Hausdorff维数和X(Q)一致维数上界的结果．     

不分明集的σX-级数收敛及σS-序列紧性(英文)

本文研究了不分明集的一些级数收敛性 ,给出了不分明集的σX-级数收敛定义及σS-序列紧致性 .证明了一个在论域上逐点收敛的模订级数 ,将在某种中的拓扑下 ,也可以是收敛的 .如论域 X为紧度量空间 ,且 Ai ∈ F( X)∩ C( X)时 ,级数∑∞i=1Ai 依距离 d( A,B) =supx∈ X|A( x) -B( x) |收敛     

强向量拟均衡问题解的存在性(英文)

设X是一个实的Hausdorff拓扑向量空间,Y是一个实的局部凸向量空间,C是Y中的闭凸锥,K（?）X是一个紧子集.F:X×X→Y是一个双向量函数,G:K→2K是一个集合值映射.我们考虑下面的强拟均衡问题:存在x∈G（x）,使得对任意的y∈G（x）,成立F（x,y）∈C.本文证明了当F是半连续时,上述问题解的存在性结论.     

线载荷积分方程法分析桩顶受任意荷载的弹性斜桩

嵌在各向同性均匀弹性半空间的弹性斜桩顶部,受任意荷载的位移和应力,可分解为在倾斜平面xOz及其法平面yOz内进行分析.将Mindlin力作为基本虚载荷,令集度为未知函数X(t)、Y(t)、Z(t),分别平行于x、y、z轴,的基本载荷沿桩轴t的[0,L]内分布,并在桩顶作用集中力Q_x,Q_y、Z,力偶矩M_y、M_x,根据弹性桩的边界条件,将问题归结为一组Fredholm-Volera型的积分方程.文中给出数值解.计算结果的精度可用功的互等定理来检查.     

Banach空间的正规结构与对径点

假设S（X）是Banach空间X的单位球面,作引进了四个新的几何参数：Jε（X）=sup{βε（x）,x∈S（X）},jε（X）=inf{βε（x）,x∈S（X）},Gε（X）=sup{αε（x）,x∈S（X）},gε（X）=inf{αε（x）,x∈S（S）},其中≤ε≤1,βε（x）=sup{min{‖x εy‖,‖x-εy‖,y∈S（X）}},αε（x）=inf{max{‖x εy‖,‖x-εy‖,y∈S（X）}},讨论了这些参数的性质,本主要结果是：如果主要结果是：如果有一个ε,0≤ε≤1,使得Jε（X）＜1 ε/2或gε（X）＞1 ε/3,那末X有一至正规结构。     

Maximum Principle of Semi-Linear Distributed System (I)

In this paper, an optimal control problem of non-linear Volterra systems $x(\cdot)=h(t)+\int_0^t G(t,s)f(s,x(s),u(s))ds$ on Banach space X with a general cost functional $Q(u(\cdot)) = \int_0^T J(s,x(s,u(\cdot)),u(s))ds$ is discussed, where $G(t,s)\in \varphi(X)$ is strongly continuous in (t, s), h(\cdot)\in C([0,T],G),f(s,x,u):[0,T]*X*U \rightarrow X and J (s, x, u) : [0, T] *X*U \rightarrow R. The control region U is an arbitrary set in a Banach space. Under some other assumptions of f and J, we have proved the following Theorem. The optimal control u^*(\cdot) of the above problem satisfies max $H(t,u)=H(t,u^*(t))$ for a.e.t\in [0,T], Where $H(t,u)=-J(t,x^*(t),u)+(\phi(t),f(t,x^*(t),u))$, $\phi(t)=\int_t^T J_x(s,x^*(s),u^*(s))U(s,t)ds$ and $x^*(t)=x(t,u^*(\cdot)),U(s,t)\in \phi(X)$ is the solution of $U(s,t)=G(s,t)+\int _t^s G(s,w)f_x(w,x^*(w),u^*(w))U(w,t)dw$. We have applied the results to semi-linear distributed systems.     

Maximal inequalities for a continuous semimartingale

Let X =( X t ) t S 0 be a continuous semimartingale given by d X t = f ( t ) w ( X t )d d M ¢ t + f ( t ) σ ( X t )d M t , X 0 =0, where M =( M t , F t ) t S 0 is a continuous local martingale starting at zero with quadratic variation d M ¢ and f ( t ) is a positive, bounded continuous function on [0, X ), and w , σ both are continuous on R and σ ( x )>0 if x p 0. Denote X 𝜏 * =sup 0 h t h 𝜏 | X t | and J t = Z 0 t f ( s ) } ( X s )d d M ¢ s ( t S 0) for a nonnegative continuous function } . If w ( x ) h 0 ( x S 0) and K 1 | x | n σ 2 ( x ) h | w ( x )| h K 2 | x | n σ 2 ( x ) ( x ] R , n >0) with two fixed constants K 2 S K 1 >0, then under suitable conditions for } we show that the maximal inequalities c p , n log 1 n +1 (1+ J 𝜏 ) p h Á X 𝜏 * Á p h C p , n log 1 n +1 (1+ J 𝜏 ) p (0< p < n +1) hold for all stopping times 𝜏 .     

Zeros of accretive operators

In the investigation of accretive operators in Banach spaces X, the existence of zeros plays an important role, since it yields surjectivity results as well as fixed point theorems for operators S such that I-S is accretive. Let D?X and T: D→X an operator such that the initial value problems (1) u′(t)=-Tu(t), u(0)=x εD are solvable. Then T has a zero iff (1) has a constant solution for some xεD. Under certain assumptions on D and T it is possible to show that (1) has a unique solution u(t,x) on [0,∞), for every xεD. In this case, define U(t): D→D by U(t)x=u(t,x). If T is accretive it turns out that U(t) is nonexpansive for every t≥0. This fact constitutes the basis for several authors concerned with this subject. They proceed with assumptions on D and X ensuring either that the U(t) must have a common fixed point x_o or that U(_p) has a fixed point x_p for every p≥0. In the first case, U(t)x_o is a constant solution of (1), whence Tx_o=0. In the second case, U(t)x_p is a p-periodic solution of (1). Hence, one has to impose additional conditions on T which imply that a p-periodic solution must be constant, for some p>0. The main purpose of the present paper is to show that, in certain situations, either the operators U(t) are actually strict contractions or T may be approximated by operators T_n such that the corresponding U_n(t) are strict contractions. Thus, we obtain several results in general Banach spaces and a unification of some results in special spaces.     

Vector Variational Inequalities and the (S)<Subscript>+</Subscript> Condition

Let $${\cal Z}$$ and X be Hausdorff real topological vector spaces and let $${\cal L}_b(X,{\cal Z})$$ be the space of continuous linear mappings from X into $${\cal Z}$$ equipped with the topology of bounded convergence. In this paper, we define the (S)₊ condition for operators from a nonempty subset of X into $${\cal L}_b(X,{\cal Z})$$ and derive some existence results for vector variational inequalities with operators of the class (S)₊. Some applications to vector complementarity problems are given.     

加权经验累计分位函数的弱收敛

记(X,Y)为二元随机变量,F(x)为X的边缘分布函数.定义Y关于X的分位回归函数为h(u)=E(Y|F(X)=u),记S(u)=∫u0J(t)h(t)dt为加权累计分位回归函数,其中J(@)为权函数.本文讨论了S(u)的经验版本的弱收敛性质.     

Periodic solution of neutral Lotka-Volterra system with periodic delays

A nonautonomous n-species Lotka-Volterra system with neutral delays is investigated. A set of verifiable sufficient conditions is derived for the existence of at least one strictly positive periodic solution of this Lotka-Volterra system by applying an existence theorem and some analysis techniques, where the assumptions of the existence theorem are different from that of Gaines and Mawhin's continuation theorem [R.E. Gaines, J.L. Mawhin, Coincidence Degree and Nonlinear Differential Equations, Springer-Verlag, Berlin, 1977] and that of abstract continuation theory for k-set contraction [W. Petryshyn, Z. Yu, Existence theorem for periodic solutions of higher order nonlinear periodic boundary value problems, Nonlinear Anal. 6 (1982) 943-969]. Moreover, a problem proposed by Freedman and Wu [H.I. Freedman, J. Wu, Periodic solution of single species models with periodic delay, SIAM J. Math. Anal. 23 (1992) 689-701] is answered.