闭值域算子的摄动

The Perturbation for Operators with Closed Range

本文给出了T+A具有闭值域的一个充要条件,其中T是有闭值域的算子。

In this note a sufficient and necessary condition for T + A to have closed range is given, where T is a closed operator with closed range and ‖A‖<m(?) (T) (the essential minimum modulus of T).