Inverse-closedness of the set of integral operators with $L_1$-continuously varying kernels

摘要

Let $N$ be an integral operator of the form $\bigl(Nu\bigr)(x)=\int_{\mathbbR^c}n(x,x-y)\,u(y)\,dy$ acting in $L_p(\mathbb R^c)$ with a measurable kernel$n$ satisfying the estimate $|n(x,y)|\le\beta(y)$, where $\beta\in L_1$. It isproved that if the function $t\mapsto n(t,\cdot)$ is continuous in the norm of$L_1$ and the operator $\mathbf1+N$ has an inverse, then$(\mathbf1+N)^{-1}=\mathbf1+M$, where $M$ is an integral operator possessingthe same properties.