Profile classes and partial well-order for permutations
The electronic journal of combinatorics, Permutation Patterns, Tome 9 (2002) no. 2
It is known that the set of permutations, under the pattern containment ordering, is not a partial well-order. Characterizing the partially well-ordered closed sets (equivalently: down sets or ideals) in this poset remains a wide-open problem. Given a $0/\pm1$ matrix $M$, we define a closed set of permutations called the profile class of $M$. These sets are generalizations of sets considered by Atkinson, Murphy, and Ruškuc. We show that the profile class of $M$ is partially well-ordered if and only if a related graph is a forest. Related to the antichains we construct to prove one of the directions of this result, we construct exotic fundamental antichains, which lack the periodicity exhibited by all previously known fundamental antichains of permutations.
DOI :
10.37236/1689
Classification :
06A07, 68R05, 06A06, 05A05
Mots-clés : restricted permutation, forbidden subsequence, partial well-order, well-quasi-order
Mots-clés : restricted permutation, forbidden subsequence, partial well-order, well-quasi-order
@article{10_37236_1689,
author = {Maximillian M. Murphy and Vincent R. Vatter},
title = {Profile classes and partial well-order for permutations},
journal = {The electronic journal of combinatorics},
year = {2002},
volume = {9},
number = {2},
doi = {10.37236/1689},
zbl = {1034.06005},
url = {http://geodesic.mathdoc.fr/articles/10.37236/1689/}
}
Maximillian M. Murphy; Vincent R. Vatter. Profile classes and partial well-order for permutations. The electronic journal of combinatorics, Permutation Patterns, Tome 9 (2002) no. 2. doi: 10.37236/1689
Cité par Sources :