On the Moebius function of the quasi-consecutive pattern poset
Antonio Bernini, Luca Ferrari · Florence Research (University of Florence) · 2014
We define the quasi consecutive pattern poset by declaring \\sigma \\leq \\tau whenever the permutation \\tau contains an occurrence of the permutation \\sigma in which all the entries are adjacent in \\tau except at most the first and the second. We then investigate the Moebius function of the quasi consecutive pattern poset and we completely determine it for those intervals [\\sigma ,\\tau ] such that \\sigma occurs precisely once in \\tau.