Author(s): Gran, Marino ; Rodelo, Diana ; Nguefeu, Idriss Tchoffo
Date: 2020
Persistent ID: https://hdl.handle.net/10316/89452
Origin: Estudo Geral - Universidade de Coimbra
Subject(s): Mal'tsev categories; Goursat categories; Congruence distributive varieties; Shifting Lemma; Triangular Lemma; Trapezoid Lemma
We give new characterisations of regular Mal'tsev categories with distributive lattice of equivalence relations through variations of the so-called Triangular Lemma and Trapezoid Lemma in universal algebra. We then give new characterisations of equivalence distributive Goursat categories (which extend 3-permutable varieties) through variations of the Triangular and Trapezoid Lemmas involving reflexive and positive relations.
