Pointwise-generalized-inverses of linear maps between C${}^{\ast }$-algebras and JB${}^{\ast }$-triples

Abstract

We study pointwise-generalized-inverses of linear maps between C${}^{\ast }$-algebras. Let $\Phi$ and $\Psi$ be linear maps between complex Banach algebras $A$ and $B$. We say that $\Psi$ is a pointwise-generalized-inverse of $\Phi$ if $\Phi (aba)=\Phi (a)\Psi (b)\Phi (a),$ for every $a,b\in A$. The pair $(\Phi ,\Psi )$ is Jordan-triple multiplicative if $\Phi$ is a pointwise-generalized-inverse of $\Psi$ and the latter is a pointwise-generalized-inverse of $\Phi$. We study the basic properties of this maps in connection with Jordan homomorphism, triple homomorphisms and strongly preservers. We also determine conditions to guarantee the automatic continuity of the pointwise-generalized-inverse of continuous operator between C${}^{\ast }$-algebras. An appropriate generalization is introduced in the setting of JB${}^{\ast }$-triples.