Showing math.CTShow all
3 papers · 1 filter
math.CT2025
Axioms for the category of sets and relations
Andre Kornell
We provide axioms for the dagger category of sets and relations that recall recent axioms for the dagger category of Hilbert spaces and bounded operators.
math.CT2025
Axioms for the category of Hilbert spaces and linear contractions
Chris Heunen, Andre Kornell, Nesta van der Schaaf
The category of Hilbert spaces and linear contractions is characterised by elementary categorical properties that do not refer to probabilities, complex numbers, norm, continuity,…
math.CT2024
The category of topological spaces and open maps does not have products
Guram Bezhanishvili, Andre Kornell
We prove that the category of topological spaces and open maps does not have binary products, thus resolving the Esakia problem in the negative. We also prove that the categories o…