Descent for Priestley Spaces

Descent for Priestley Spaces

A characterization of descent morphism in the category of Priestley spaces, as well as necessary and sufficient conditions for such morphisms to be effective are given. For that we embed this category in suitable categories of preordered topological spaces were descent and effective morphisms are described using the monadic description of descent.

Stone Spaces versus Priestley Spaces

[1] B. Banaschewski, Über nulldimensionale Räume, Math. Nache 13 (1955) 129-140. [2] F. Borceux and J. Janelidze, Galois Theories, Cambridge University Press (2001). [3] M. Dias and M. Sobral, Descent for Priestley Spaces, Appl. Categor. Struct 14 (2006) 229-241. [4] B. A. Davey and H. A. Priestley, Introduction to Lattices and Order, Cambridge Mathematical Texbooks (1990). [5] R. Engelking and...

The Priestley Separation Axiom for Scattered Spaces

Let R be a quasi-order on a compact Hausdorff topological space X. We prove that if X is scattered, then R satisfies the Priestley separation axiom if and only if R is closed in the product space X × X. Furthermore, if X is not scattered, then we show that there is a quasi-order on X that is closed in X × X but does not satisfy the Priestley separation axiom. As a result, we obtain a new charac...

Forbidden Forests in Priestley Spaces

We present a first order formula characterizing the distributive lattices L whose Priestley spaces P(L) contain no copy of a finite forest T . For Heyting algebras L, prohibiting a finite poset T in P(L) is characterized by equations iff T is a tree. We also give a condition characterizing the distributive lattices whose Priestley spaces contain no copy of a finite forest with a single addition...

Configurations in Coproducts of Priestley Spaces