Profinite relational structures

• Autor(es): Janelidze, George ; Sobral, Manuela
• Data: 2008
• Identificador Persistente: http://hdl.handle.net/10316/11239
• Origem: Estudo Geral - Universidade de Coimbra
• Assunto(s): Ordered (preordered) topological spaces; Priestley space; Stone space; Fibration; Topological functor; Profinite; Relational structure; Quasi-variety
• Tipo de Documento: Preprint
• Idioma: Inglês

Descrição

We show that a topological preorder (on a Stone space) is profinite if and only if it is inter-clopen, i.e. it can be presented as an intersection of closed-andopen preorders on the same space. In particular this provides a new characterization of the so-called Priestley spaces. We then extend this from preorders to general relational structures satisfying some conditions. We also give a stronger condition that has a rather clear model-theoretic meaning. South African NRF; FCT/Centro de Matemática da Universidade de Coimbra