Approximation properties of torsion classes
Logic
2024-09-27 v2 Commutative Algebra
Category Theory
Rings and Algebras
Abstract
We strengthen a result of Bagaria and Magidor~\cite{MR3152715} about the relationship between large cardinals and torsion classes of abelian groups, and prove that (1) the \emph{Maximum Deconstructibility} principle introduced in \cite{Cox_MaxDecon} requires large cardinals; it sits, implication-wise, between Vop\v{e}nka's Principle and the existence of an -strongly compact cardinal. (2) While deconstructibility of a class of modules always implies the precovering property by \cite{MR2822215}, the concepts are (consistently) non-equivalent, even for classes of abelian groups closed under extensions, homomorphic images, and colimits.
Cite
@article{arxiv.2406.02829,
title = {Approximation properties of torsion classes},
author = {Sean Cox and Alejandro Poveda and Jan Trlifaj},
journal= {arXiv preprint arXiv:2406.02829},
year = {2024}
}