3 papers
math.FA2026
Local-to-Global Isometries in Standard-Norm Generalized Gyrovector Spaces: Thompson and Hilbert Geometries of JB-Cones
Jyamira Oppekepenguin
We introduce standard-norm generalized gyrovector spaces: generalized gyrovector spaces whose norm-value line has the ordinary real operations and whose fixed scalar maps are conti…
math.FA2026
On the Fischer-Muszély equation for the positive cones of -algebras
Daisuke Hirota, Jyamira Oppekepenguin
We study the Fischer-Muszély functional equation for the positive semidefinite and the positive definite cones of unital -algebras. We show that any bijection between the posi…
math.FA2025
Spectral decomposition of power-bounded operators: The finite spectrum case
Shiho Oi, Jyamira Oppekepenguin
In this paper, we investigate power-bounded operators, including surjective isometries, on Banach spaces. Koehler and Rosenthal asserted that an isolated point in the spectrum of a…