An addendum to "The theory of implicit operations"
Rings and Algebras
2026-01-05 v1 Logic
Abstract
In this addendum to [4], we provide a pair of counterexamples relevant to the theory of implicit operations. More precisely, we exhibit a pp expansion of a variety that fails to be a variety (although it is a quasivariety). Furthermore, we construct a sequence of varieties possessing a nonequational congruence preserving Beth companion.
Keywords
Cite
@article{arxiv.2601.00006,
title = {An addendum to "The theory of implicit operations"},
author = {Luca Carai and Miriam Kurtzhals and Tommaso Moraschini},
journal= {arXiv preprint arXiv:2601.00006},
year = {2026}
}
Comments
Addendum to arXiv:2512.14326