一类两个相同部件并联的可修系统的适定性

用C0－半群理论证明一类两个相同部件并联可修系统的非负解的存在唯一性。  

强耦合反应扩散方程组的定性分析

本文研究由四个反应扩散方程组成的强耦合方程组，利用算子半群理论，上、下解方法和能量积分等经典分析方法，论证此类方程组的整体解的存在唯一性和有界性。  

具有未知源的某些非线性伪抛物型方程的反问题

考 虑具有未 知源项的 某些非 线性伪 抛物 型方程 的反演 问题． 首先 将伪抛 物型 方程初 边值问 题化为非线 性发展方 程 Ｃｏｕｃｈ ｙ 问题，然 后，利用半 群理论，论 证发展 方程反问 题解的存 在唯一 性，最后， 利用不 动点方法得到 伪抛物型方程反 问题的可解性  

Local and global strong solutions to continuous coagulation-fragmentation equations with diffusion

We consider the diffusive continuous coagulation-fragmentation equations with and without scattering and show that they admit unique strong solutions for a large class of initial values. If the latter values are small with respect to a suitable norm, we provide sufficient conditions for global-in-time existence in the absence of fragmentation.  

Boundary controllability of Sobolev-type abstract nonlinear integrodifferential systems

Sufficient conditions are established for boundary controllability of various classes of Sobolev-type nonlinear systems including integrodifferential systems in Banach spaces. The results are obtained using the strongly continuous semigroup of operators and the Banach contraction principle. Examples are provided to illustrate the theory.  

On the periodic Wigner-Poisson-Fokker-Planck system

This paper is concerned with the existence and uniqueness analysis of global classical solutions of a diffusive quantum evolution equation with nonlinear coupling to the Poisson equation. The main technical difficulty in the existence proof is to show that the quantum Fokker-Planck term is a semigroup-generator in a weighted L²-space. The potential term is then a Lipschitz perturbation of it.  

Controllability of Nonlinear Systems in Banach Spaces: A Survey

This paper presents a survey on research using fixed-point theorems and semigroup theory to study the controllability of nonlinear systems and functional integrodifferential systems in Banach spaces. Also discussed is the use of this technique in K-controllability and boundary controllability problems for nonlinear systems and integrodifferential systems in abstract spaces.  

Boundary controllability of integrodifferential systems in Banach spaces

Sufficient conditions for boundary controllability of integrodifferential systems in Banach spaces are established. The results are obtained by using the strongly continuous semigroup theory and the Banach contraction principle. Examples are provided to illustrate the theory.  

Some analytical semigroups occurring in probability theory

One-parameter semigroups occurring in operator-limit distributions are investigated. The topological-algebraic background of the relevant monoids is discussed and Lie semigroup theory is applied to the Urbanik Decomposability Semigroup.  

Semigroup approach for the approximation of a control problem with unbounded dynamics

In this paper, we approximate a control problem in an infinite-dimensional Hilbert space by means of a sequence of discrete problems. In the differential equation which describes the dynamics, a Lipschitz perturbation of an unbounded linear operator appears. We prove a convergence result of the approximation value functions to the value function of the original problem.This research was supported by Ministero dell'Università e della Ricerca Scientifica e Technologica and by Consiglio Nazionale delle Ricerche, Rome, Italy.