Some results on the sum of linear operator with nondense domains
Suppose that A and B are closed, not necessarily densely defined, linear operators on a complex Banach space. The author shows under certain technical assumptions that the closure of \(A+B\) has an extension which has a nonempty resolvent and he characterizes certain interpolation spaces containing the domain of this extension.
closed, not necessarily densely defined, linear operators on a complex Banach space
scientific article; zbMATH DE number 4171733