On the pseudospectrum preservers
On the pseudospectrum preservers
Let X and Y be two complex Banach spaces, and let B(X) denotes the algebra of all bounded linear operators on X. We characterize additive maps from B(X) onto B(Y ) compressing the pseudospectrum subsets Δϵ(.), where Δϵ (.) stands for any one of the spectral functions σϵ (.), σlϵ …