activity
20092026
most citedMultiplicatively spectrum-preserving and norm-preserving maps between invertible groups of commutative Banach algebras

18 citations · 27 across the 18 of their papers we have counts for

collaborators

18 papers

math.FA2026

Spectral decomposition of doubly power-bounded elements in Banach algebras

Osamu Hatori, Shiho Oi

We establish a characterization of doubly power-bounded elements with finite spectrum in Banach algebras. In particular, we present a spectral decomposition for such elements, exte…

math.FA2024

Generalized gyrovector spaces revisited

Toshikazu Abe, Osamu Hatori

We revise a proof of a Mazur-Ulam theorem for generalized gyrovector spaces.

math.FA2022

The Mazur-Ulam property for a Banach space which satisfies a separation condition

Osamu Hatori

We study -rich spaces, lush spaces, and -extremely regular spaces concerning with the Mazur-Ulam property. We show that a uniform algebra and the real part of a uniform algeb…

math.FA2021

The Mazur-Ulam property for uniform algebras

Osamu Hatori

We give a sufficient condition for a Banach space with which the homogeneous extension of a surjective isometry from the unit sphere of it onto another one is real-linear. The cond…

math.FA2021

Tingley's problem on uniform algebras

Osamu Hatori, Shiho Oi, Rumi Shindo Togashi

We prove that a surjective isometry between the unit spheres of two uniform algebras is extended to a surjective real-linear isometry between the uniform algebras. It provides the…

math.FA2018★ 4 cited

2-local isometries on function spaces

Osamu Hatori, Shiho Oi

We study 2-local reflexivity of the set of all surjective isometries between certain function spaces. We do not assume linearity for isometries. We prove that a 2-local isometry in…