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On dual Ramsey theorems for relational structures

Dragan Mašulović (2020)

Czechoslovak Mathematical Journal

We discuss dual Ramsey statements for several classes of finite relational structures (such as finite linearly ordered graphs, finite linearly ordered metric spaces and finite posets with a linear extension) and conclude the paper with another rendering of the Nešetřil-Rödl Theorem for relational structures. Instead of embeddings which are crucial for ``direct'' Ramsey results, for each class of structures under consideration we propose a special class of quotient maps and prove a dual Ramsey theorem...

On extended frames

Jorge Picado (1995)

Commentationes Mathematicae Universitatis Carolinae

Some aspects of extended frames are studied, namely, the behaviour of ideals, covers, admissible systems of covers and uniformities.

On fuzzification of the notion of quantaloid

Sergey A. Solovyov (2010)

Kybernetika

The paper considers a fuzzification of the notion of quantaloid of K. I. Rosenthal, which replaces enrichment in the category of -semilattices with that in the category of modules over a given unital commutative quantale. The resulting structures are called quantale algebroids. We show that their constitute a monadic category and prove a representation theorem for them using the notion of nucleus adjusted for our needs. We also characterize the lattice of nuclei on a free quantale algebroid. At...

On hereditary and product-stable quotient maps

Friedhelm Schwarz, Sibylle Weck-Schwarz (1992)

Commentationes Mathematicae Universitatis Carolinae

It is shown that the quotient maps of a monotopological construct A which are preserved by pullbacks along embeddings, projections, or arbitrary morphisms, can be characterized by being quotient maps in appropriate extensions of A.

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