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Splitting finite antichains in the homomorphism order

2008/01/15 by Jan Foniok, Foniok, Jan, Jaroslav Nesetril +1
Mathematics · #05C15 #06D05 #Combinatorics (math.CO) #FOS: Mathematics #math.CO #msc:05C15 #msc:06D05

paper · pdf · doi:10.48550/arxiv.0801.2384

10 pages

arxiv created 2008/03/09 · arxiv updated 2009/12/01

Abstract

A structural condition is given for finite maximal antichains in the homomorphism order of relational structures to have the splitting property. It turns out that non-splitting antichains appear only at the bottom of the order. Moreover, we examine looseness and finite antichain extension property for some subclasses of the homomorphism poset. Finally, we take a look at cut-points in this order.

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