Title
Regular families of forests, antichains and duality pairs of relational structures
Abstract
Homomorphism duality pairs play a crucial role in the theory of relational structures and in the Constraint Satisfaction Problem. The case where both classes are finite is fully characterized. The case when both sides are infinite seems to be very complex. It is also known that no finite-infinite duality pair is possible if we make the additional restriction that both classes are antichains. In this paper we characterize the infinite-finite antichain dualities and infinite-finite dualities with trees or forests on the left hand side. This work builds on our earlier papers [6] that gave several examples of infinite-finite antichain duality pairs of directed graphs and [7] giving a complete characterization for caterpillar dualities.
Year
DOI
Venue
2017
10.1007/s00493-015-3003-4
Combinatorica
Keywords
Field
DocType
68Q19, 05C05
Discrete mathematics,Combinatorics,Antichain,Directed graph,Constraint satisfaction problem,Duality (optimization),Homomorphism,Mathematics
Journal
Volume
Issue
ISSN
37
4
1439-6912
Citations 
PageRank 
References 
1
0.36
9
Authors
4
Name
Order
Citations
PageRank
Péter L. Erdös126746.75
Dömötör Pálvölgyi2153.79
Claude Tardif334138.08
Gábor Tardos41261140.58