3 papers
math.CO2016
Isometric copies of directed trees in orientations of graphs
Taras Banakh, Adam Idzik, Oleg Pikhurko +2
For every we construct a finite graph such that every orientation of contains an isometric copy of any oriented tree on vertices, and evaluate…
math.CO2014
On -transitive closures of directed paths
Krzysztof Pszczoła
In this paper we study the structure of -transitive closures of directed paths and formulate several properties. Concept of -transitive orientation generalize the traditional…
math.RA2012
Dualities between finitely separated structures
Wiesław Kubiś, Krzysztof Pszczoła
We study dualities between classes of relational topological structures, given by Hom-functors. We show that there exists a 2-element structure with infinitely many relations, whic…