Partially defined σ-derivations on semisimple Banach algebras
Partially defined σ-derivations on semisimple Banach algebras
Let $A$ be a semisimple Banach algebra with a linear automorphism ${\sigma}$ and let $\delta\colon I\rightarrow A$ be a ${\sigma}$-derivation, where $I$ is an ideal of $A$. Then $\Phi(\delta)(I\cap{\sigma}(I) )=0$, where $\Phi(\delta)$ is the separat