Theodore Dokos

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Call two sequences of distinct integers a1a2 . . . ak and b1b2 . . . bk order isomorphic if they have the same pairwise comparisons, i.e., ai < aj if and only if bi < bj for all indices i, j. For example 132 and 475 are order isomorphic since both begin with the smallest element, have the largest element second, and end with the middle sized element. Let Sn(More)
Ascent sequences were introduced by Bousquet-Mélou, Claesson, Dukes and Kitaev in their study of (2 + 2)-free posets. An ascent sequence of length n is a nonnegative integer sequence x = x1x2 . . . xn such that x1 = 0 and xi ≤ asc(x1x2 . . . xi−1) + 1 for all 1 < i ≤ n, where asc(x1x2 . . . xi−1) is the number of ascents in the sequence x1x2 . . . xi−1. We(More)
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