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Probability and Combinatorics

Tuesday, February 20, 2018 - 3:00pm

Cheyne Homberger

University of Maryland


University of Pennsylvania


The breadth of a permutation π is the minimum value of |i - j| + |π(i) - π(j)|, taken over all relevant i and j. Breadth has important consequences to permutation pattern containment, and connections to plane tiling. In this talk we explore the breadth of random permutations using both probabilistic techniques and combinatorial geometry. In particular, we present the expected breadth of a random permutation, the proportion of permutations with a fixed breadth, and a constructive proof for maximizing unique large patterns in permutations.  This talk is based on work with both David Bevan and Bridget Tenner and with Simon Blackburn and Pete Winkler.