Eventos > Seminários de Álgebra

Congruence classes of varieties of algebras

13/09/2013 Sexta-feira, 13 de Setembro de 2013, 15:45-16:45, IIIUL - Sala B1-01 
Pierre Gillibert (CAUL)
Instituto para a Investigação Interdisciplinar da Universidade de Lisboa

The congruence class of a variety of algebras is the class of all isomorphic copies of congruences lattices of algebras in the variety. Most of this talk resolves around the following two questions: Is it possible to characterize lattices in a given congruence class? To which extent a variety of algebras is determines by its congruence class? The first question seems very difficult. It is even difficult, for a given class, to prove that a will-to-be characterization is not valid. However, there is an efficient tool that allows to distinguish congruence classes, based on poset-indexed diagrams of algebras. I shall illustrate it with several examples.