Work

The Malt'sev condition for groups is not categorical

Year: 2026
Type: preprint
Abstract: In this paper we prove that the Mal'tsev condition expressing the existence of group operations is not equivalent to a categorical property. More precisely, using pseudo-invertible idempotents, we construct two varieties $\mathcal{V}$ and $\mathcal{V}(f)$ which are equivalent as categories, and such that $\mathcal{V}$ admits group operations, whereas $\mathcal{V}(f)$ does not. We also show that those Mal'tsev conditions which are equivalent to a categorical property have a trivial spectrum.
Language: English
Open Access status: green
OpenAlex ID: W7223682100
Cites: 3
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Related to: 10