A generalization of Banach's lemma and its applications to perturbations of bounded linear operators

Let X be a Banach space and let P:X→X be a bounded linear operator.Using an algebraic inequality on the spectrum of P,we give a new sufficient condition that guarantees the existence of(I-P)^(-1) as a bounded linear operator on X,and a bound on its spectral radius is also obtained.This generalizes the classic Banach lemma.We apply the result to the perturbation analysis of general bounded linear operators on X with commutative perturbations.

基于分片线性最大Rényi熵的Fredholm积分方程数值解法

大部分积分方程无法求出精确解,因此需考虑数值方法得到近似解。提出了一种基于分片线性基函数的最大Rényi熵的函数恢复方法,证明了解的唯一性,并在此基础上给出基于分片线性最大Rényi熵的Fredholm积分方程数值解法。数值实验表明:基于分片线性最大Rényi熵的Fredholm积分方程数值解法有效,且可以得到比基于分片线性最大Shannon熵的数值解法精度更高的解。