Banach空间积分双半群的生成条件

研究Banach空间中积分双半群的生成条件.利用算子A的豫解算子,给出了积分双半群T(t)的生成定理.结果表明:如果对任意的x∈X,f∈X*,以及A|λ]<δ,λ∈ρ(A),有∈Lp(R),则存在算子族S(t),t∈R,S(t)强连续且满足积分双半群的定义.     

正则预解算子族的乘积扰动

设K∈C（R＋）和B是一个有界线性算子．作者证明如果犃生成一个指数有界的A正则预解算子族，那么BA，AB或A（I＋B），（I＋B）A也生成一个指数有界的k-正则预解算子族．此外，作者也给出了k正则预解算子族的加法扰动的相应结果．     

退化正则半群

引入了退化正则半群的定义，给出退化正则半群的一些基本性质，并证明了用多值线性算子刻划的指数有界退化正则半群的生成定理．     

关于双参数半群的诱导半群

双参数算子半群概念是由于研究非时齐马氏过程产生的。由于它的复杂性,目前国内外对它的研究很少,文献不多,胡迪鹤教授在[1]中研究了双参数半群的连续性,可微性和拉氏变换,以及由转移函数产生的双参数半群的性质。本文在[1]的基础上,引进了双参数半群的诱导半群的概念,证明了双参数半群由其诱导半群的无穷小算子唯一确定,类似于Hille—Yosida 定理,对于给定的一族算子 R(?),给出了存在某双参数半群其诱导半群的预解算子族为 R(?)的充要条件。     

一类无穷维Hamilton算子的半群生成定理

研究了无穷维H am ilton算子生成C0半群的问题,得到了类无穷维H am ilton算子生成C0半群的一个充分条件.把结果应用在一类双曲型混合问题生成的无穷维H am ilton算子上,证明此类算子生成C0半群,并利用H ille-Y osida定理进一步说明了结果的正确性和有效性.另外,还给出了波动方程相应的无穷维H am ilton算子所生成的C0半群的具体表达式.     

关于强拓扑对偶多重Hilbert空间上连续线性算子的（C_0，1）－发展系

本文证明：若强对偶多重Ｈｉｌｂｅｒｔ空间上的（Ｃ＿０，１）－半群族的无穷小生成算子族是г－稳定的，则该半群族生成г－稳定的发展系．基于此，本文还得出了关于（Ｃ＿０，１）－发展系的一个摄动定理．     

双连续N次积分C-半群的逼近定理

在C0半群和双连续半群逼近定理的启发下,讨论了双连续n次积分C-半群的逼近定理.     

指数有界双连续α次积分C半群的扰动

在α次积分C半群和双连续n次积分C半群的基础上,探讨了双连续α次积分C半群的扰动性,得到了双连续α次积分C半群的扰动定理,并且在局部Lipschitz连续条件下证明双连续α次积分C半群的扰动理论仍然成立.     

一类二阶奇异抽象微分方程的半群解

应用积分算子H^Pa,2,强连续算子c（t）,半群算子T（t）研究一类二阶奇异抽象微分方程的初值问题,找到该方程存在适定解的充要条件以及半群解的表达式,并给出Bessel算子与半群算子生成元间的关系．作为特例,给出一类特殊奇异方程的半群解以及它的生成元与cosine算子生成元间的关系．     

双连续半群的概率饱和定理

利用Riemann-stieltjes随机过程、矩生成函数及算子值数学期望讨论了双连续C_0半群的概率逼近问题给出了指数有界的双连续C_0半群的概率饱和定理.     

Characteristic Conditions for the Generation of α-Times Resolvent Families on a Hilbert Space

In 2000,Shi and Feng gave the characteristic conditions for the generation of C0semigroups on a Hilbert space.In this paper,we will extend them to the generation of α-times resolvent operator families.Such characteristic conditions can be applied to show rank-1 perturbation theorem and relatively-bounded perturbation theorem for α-times resolvent operator families.     

双连续n次积分C余弦函数的逼近定理

基于双连续半群概念,引入一致双连续半群序列概念,借助Laplace变换和Trotter-Kato定理,考察双连续n次积分C余弦函数与C-预解式之间的关系,得到逼近定理的稳定性条件,进而得出双连续n次积分C余弦函数逼近定理.从而对Banach空间强连续半群逼近定理和双连续半群逼近定理进行了推广,为相应抽象的Cauchy问题提供了解决方案.     

Hilbert空间上$\alpha$-次预解算子族的生成元特征

In 2000,Shi and Feng gave the characteristic conditions for the generation of C0semigroups on a Hilbert space.In this paper,we will extend them to the generation of α-times resolvent operator families.Such characteristic conditions can be applied to show rank-1 perturbation theorem and relatively-bounded perturbation theorem for α-times resolvent operator families.     

指数有界的双连续n次积分C-半群及其生成定理

在双连续半群和n次积分C-半群的基础上,引入了指数有界的双连续n次积分C-半群,并讨论了其性质和生成定理.     

Duality theory of regularized resolvent operator family

Let \( k \in C(R^+)\), A be a closed linear densely defined operator in the Banach&nbsp;space \(X\) and \( \{R(t)\}_{t\geq 0} \) be an exponentially bounded \(k\)-regularized resolvent operator families&nbsp;generated by A. In this paper, we mainly study pseudo k-resolvent and duality theory&nbsp;of k-regularized resolvent operator families. The conditions that pseudo k-resolvent&nbsp;become k-resolvent of the closed linear densely defined operator A are given. The&nbsp;some relations between the duality of the regularized resolvent operator families and&nbsp;the generator A are gotten. In addition, the corresponding results of duality of \(k\)-regularized resolvent operator families in Favard space are educed.     

WEAK REGULARIZATION FOR A CLASS OF ILL-POSED CAUCHY PROBLEMS

This article is concerned with the ill-posed Cauchy problem associated with a densely defined linear operator A in a Banach space. A family of weak regularizing operators is introduced. If the spectrum of A is contained in a sector of right-half complex plane and its resolvent is polynomially bounded, the weak regularization for such ill-posed Cauchy problem can be shown by using the quasi-reversibility method and regularized semigroups. Finally, an example is given.     

Product formulas,nonlinear semigroups,and accretive operators

A special case of our main theorem, when combined with a known result of Brezis and Pazy, shows that in reflexive Banach spaces with a uniformly Gâteaux differentiable norm, resolvent consistency is equivalent to convergence for nonlinear contractive algorithms. (The linear case is due to Chernoff.) The proof uses ideas of Crandall, Liggett, and Baillon. Other applications of our theorem include results concerning the generation of nonlinear semigroups (e.g., a nonlinear Hille-Yosida theorem for “nice” Banach spaces that includes the familiar Hilbert space result), the geometry of Banach spaces, extensions of accretive operators, invariance criteria, and the asymptotic behavior of nonlinear semigroups and resolvents. The equivalence between resolvent consistency and convergence for nonlinear contractive algorithms seems to be new even in Hilbert space. Our nonlinear Hille-Yosida theorem is the first of its kind outside Hilbert space. It establishes a biunique correspondence between m-accretive operators and semigroups on nonexpansive retracts of “nice” Banach spaces and provides affirmative answers to two questions of Kato.     

Perturbations of Bi-continuous Semigroups with Applications to Transition Semigroups on C<Subscript>b</Subscript>(H)

We prove an unbounded perturbation theorem for bi-continuous semigroups on the space of bounded, continuous functions on the Hilbert space H. This is applied to the Ornstein-Uhlenbeck semigroup, thus providing a purely functional analytic approach to the existence of transition semigroups on C_b(H) with bounded non-linear drift.