3 papers
math.FA2026
Surjective Fischer--Muszély maps on positive cones of JB-algebras
Osamu Hatori, Shiho Oi
We prove that every surjective Fischer--Muszély map between positive cones of arbitrary JB-algebras is additive and positively homogeneous, and extends uniquely to a bounded positi…
math.OA2024
Non-linear characterization of Jordan -isomorphisms via maps on positive cones of -algebras
Osamu Hatori, Shiho Oi
We study maps between positive definite or positive semidefinite cones of unital -algebras. We describe surjective maps that preserve (1) the norm of the quotient or multiplic…
math.FA2023
Isometries between groups of invertible elements in Fourier-Stieltjes algebras
Osamu Hatori, Shiho Oi
We prove that if open subgroups of the groups of invertible elements in two Fourier-Stieltjes algebras are isometric as metric spaces, then the underlying locally compact groups ar…