From the 1 of 6 linked papers with an AI index.
6 papers
On the Fischer-Muszély equation for the positive cones of -algebras
Daisuke Hirota, Jyamira Oppekepenguin
The paper investigates the Fischer‑Muszély functional equation on the positive semidefinite and positive definite cones of unital C*-algebras, proving that any bijection satisfying…
Surjective isometries on the positive parts of the unit spheres of some function spaces
Yuta Enami, Daisuke Hirota, Hironao Koshimizu +1
We consider the space of continuously differentiable functions on the closed unit interval and the space of Lipschitz continuous fun…
Globalization of local sign structures for phase-isometries on uniform algebras
Yuta Enami, Daisuke Hirota, Izuho Matsuzaki +1
We study surjective phase-isometries between the unit spheres of uniform algebras. Although such maps preserve maximal convex sets up to signs, the resulting local sign ambiguity p…
The Impossibility of Cohesion Without Fragmentation
Daisuke Hirota
Accounts of social division and cohesion presuppose relations whose maintenance already depends on positional compatibility. We develop this feasibility layer as a static theory: a…
Norm additive mappings between commutative -algebras in the range
Daisuke Hirota
Let \( A_i \) be a commutative \( C^{*} \)-algebra for \( i = 1, 2 \), and denote by \( A_i^{+} \) its positive cone, consisting of all positive elements of \( A_i \). In this pape…
Rational Adversaries and the Maintenance of Fragility: A Game-Theoretic Theory of Rational Stagnation
Daisuke Hirota
Cooperative systems often remain in persistently suboptimal yet stable states. This paper explains such "rational stagnation" as an equilibrium sustained by a rational adversary wh…