English

Generalized Quasiorders and the Galois Connection End-gQuord

Rings and Algebras 2023-07-06 v1

Abstract

Equivalence relations or, more general, quasiorders (i.e., reflexive and transitive binary relations) ρ\rho have the property that an nn-ary operation ff preserves ρ\rho, i.e., ff is a polymorphism of ρ\rho, if and only if each translation (i.e., unary polynomial function obtained from ff by substituting constants) preserves ρ\rho, i.e., it is an endomorphism of ρ\rho. We introduce a wider class of relations -- called generalized quasiorders -- of arbitrary arities with the same property. With these generalized quasiorders we can characterize all algebras whose clone of term operations is determined by its translations by the above property, what generalizes affine complete algebras. The results are based on the characterization of so-called u-closed monoids (i.e., the unary parts of clones with the above property) as Galois closures of the Galois connection End-gQuord, i.e., as endomorphism monoids of generalized quasiorders. The minimal u-closed monoids are described explicitly.

Keywords

Cite

@article{arxiv.2307.01868,
  title  = {Generalized Quasiorders and the Galois Connection End-gQuord},
  author = {Danica Jakubíková-Studenovská and Reinhard Pöschel and Sándor Radeleczki},
  journal= {arXiv preprint arXiv:2307.01868},
  year   = {2023}
}