Nonlinear maps preserving semi-Fredholm operators with bounded nullity
Guoxing Ji, Xia Jiao, Weijuan Shi · Quaestiones Mathematicae · 2022
Let be an infinite dimensional complex Banach space, and let be the algebra of all bounded linear operators on . In this paper, given any positive integer n, we provide a characterization of all bijective maps on preserving the difference of semi-Fredholm operators with nullity less than n, and describe completely the structure of these maps.