2025/10/28 by Kuzma, Bojan, Stefanović, Srdjan, Tanaka, Ryotaro
#46B20 #46B80 #47B49 #FOS: Mathematics #Operator Algebras (math.OA) #Primary 46L05 #Secondary 46L35
paper · doi:10.48550/arxiv.2510.24308
It is shown that every linear strong Birkhoff-James isomorphism between unital C^*-algebras is a *-isomorphism followed by a unitary multiplication. Moreover, as a partial extension of this result to the non-unital case, the form of (possibly nonlinear) strong Birkhoff-James isomorphisms between compact C^*-algebras are determined. A nonlinear characterization of compact C^*-algebras in terms of strong Birkhoff-James orthogonality is also given.