PASCAL - Pattern Analysis, Statistical Modelling and Computational Learning

Retractions onto series-parallel posets
Victor Dalmau, Andrei Krokhin and Benoit Larose
Discrete Mathematics 2008.


The poset retraction problem for a poset P is whether a given poset Q containing P as a subposet admits a retraction onto P, that is, whether there is a homomorphism from Q onto P which fixes every element of P. We study this problem for finite series-parallel posets P. We present equivalent combinatorial, algebraic, and topological charaterisations of posets for which the problem is tractable, and, for such a poset P, we describe posets admitting a retraction onto P.

EPrint Type:Article
Project Keyword:Project Keyword UNSPECIFIED
Subjects:Theory & Algorithms
ID Code:5290
Deposited By:Victor Dalmau
Deposited On:24 March 2009