Hilbert spaces admit no finitary discrete imaginaries

Fuente: arXiv
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Main Authors: Chen, Ruiyuan, Trindade, Isabel
Format: Preprint
Published: 2025
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author Chen, Ruiyuan
Trindade, Isabel
author_facet Chen, Ruiyuan
Trindade, Isabel
contents We prove that every functor from the category of Hilbert spaces and linear isometric embeddings to the category of sets which preserves directed colimits must be essentially constant on all infinite-dimensional spaces. In other words, every finitary set-valued imaginary over the theory of Hilbert spaces, in a broad signature-independent sense, must be essentially trivial. This extends a result and answers a question by Lieberman--Rosický--Vasey, who showed that no such functor on the supercategory of Hilbert spaces and injective linear contractions can be faithful.
format Preprint
id arxiv_https___arxiv_org_abs_2509_11321
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Hilbert spaces admit no finitary discrete imaginaries
Chen, Ruiyuan
Trindade, Isabel
Category Theory
Logic
18C35, 03C66
We prove that every functor from the category of Hilbert spaces and linear isometric embeddings to the category of sets which preserves directed colimits must be essentially constant on all infinite-dimensional spaces. In other words, every finitary set-valued imaginary over the theory of Hilbert spaces, in a broad signature-independent sense, must be essentially trivial. This extends a result and answers a question by Lieberman--Rosický--Vasey, who showed that no such functor on the supercategory of Hilbert spaces and injective linear contractions can be faithful.
title Hilbert spaces admit no finitary discrete imaginaries
topic Category Theory
Logic
18C35, 03C66
url https://arxiv.org/abs/2509.11321