On the longest common subsequence of conjugation invariant random permutations
The electronic journal of combinatorics, Tome 27 (2020) no. 4
Bukh and Zhou conjectured that the expectation of the length of the longest common subsequence of two i.i.d random permutations of size $n$ is greater than $\sqrt{n}$. We prove in this paper that there exists a universal constant $n_1$ such that their conjecture is satisfied for any pair of i.i.d random permutations of size greater than $n_1$ with distribution invariant under conjugation. More generally, in the case where the laws of the two permutations are not necessarily the same, we give a lower bound for the expectation. In particular, we prove that if one of the permutations is invariant under conjugation and with a good control of the expectation of the number of its cycles, the limiting fluctuations of the length of the longest common subsequence are of Tracy-Widom type. This result holds independently of the law of the second permutation.
DOI :
10.37236/8669
Classification :
60C05, 60B20, 60F05, 05A16, 05A05
Mots-clés : permutation, conjugation invariant, common sub-sequence
Mots-clés : permutation, conjugation invariant, common sub-sequence
Affiliations des auteurs :
Mohamed Slim Kammoun  1
@article{10_37236_8669,
author = {Mohamed Slim Kammoun},
title = {On the longest common subsequence of conjugation invariant random permutations},
journal = {The electronic journal of combinatorics},
year = {2020},
volume = {27},
number = {4},
doi = {10.37236/8669},
zbl = {1468.60016},
url = {http://geodesic.mathdoc.fr/articles/10.37236/8669/}
}
Mohamed Slim Kammoun. On the longest common subsequence of conjugation invariant random permutations. The electronic journal of combinatorics, Tome 27 (2020) no. 4. doi: 10.37236/8669
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