A Short Combinatorial Proof of Derangement Identity

2017/11/13 by Martinjak, Ivica, Stanić, Dajana
#05A05 #05A10 #Combinatorics (math.CO) #FOS: Mathematics

paper · doi:10.48550/arxiv.1711.04537

Abstract

The n-th rencontres number with the parameter r is the number of permutations having exactly r fixed points. In particular, a derangement is a permutation without any fixed point. We presents a short combinatorial proof for a weighted sum derangement identities.

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