{ "id": "1510.07312", "version": "v1", "published": "2015-10-25T21:50:56.000Z", "updated": "2015-10-25T21:50:56.000Z", "title": "Packing densities of layered permutations and the minimum number of monotone sequences in layered permutations", "authors": [ "Josefran de Oliveira Bastos", "Leonardo Nagami Coregliano" ], "comment": "19 pages", "categories": [ "math.CO", "cs.DM" ], "abstract": "In this paper, we present two new results of layered permutation densities. The first one generalizes theorems from H\\\"ast\\\"o [P. A. Hasto, The packing density of other layered permutations, Electron. J. Combin. 9 (2002/03), no. 2, Research paper 1, 16, Permutation patterns (Otago, 2003)] and Warren [D. Warren, Optimal packing behavior of some 2-block patterns, Ann. Comb. 8 (2004), no. 3, 355-367] to compute the permutation packing of permutations with layer sequence $(1^a,\\ell_1,\\ell_2,\\ldots,\\ell_k)$ such that $2^a-a-1\\geq k$ (and similar permutations). As a second result, we prove that the minimum density of monotone sequences of length $k+1$ in an arbitrarily large layered permutation is asymptotically $1/k^k$. This value is compatible with a conjecture from Myers [J. S. Myers, The minimum number of monotone subsequences, Electron. J. Combin. 9 (2002/03), no. 2, Research paper 4, 17 pp. (electronic), Permutation patterns (Otago, 2003)] for the problem without the layered restriction (the same problem where the monotone sequences have different lengths is also studied).", "revisions": [ { "version": "v1", "updated": "2015-10-25T21:50:56.000Z" } ], "analyses": { "subjects": [ "05A05", "05D99" ], "keywords": [ "monotone sequences", "minimum number", "packing density", "permutation patterns", "research paper" ], "note": { "typesetting": "TeX", "pages": 19, "language": "en", "license": "arXiv", "status": "editable" } } }