{ "id": "math/0503015", "version": "v2", "published": "2005-03-01T15:07:19.000Z", "updated": "2005-11-24T17:03:32.000Z", "title": "Permutation polytopes and indecomposable elements in permutation groups", "authors": [ "Robert Guralnick", "David Perkinson" ], "comment": "18 pages. To appear in the Journal of Combinatorial Theory, Series A. A corollary about solvable primitive permutation groups has been added. We have fixed some typos and made revisions according to referees' comments", "categories": [ "math.CO", "math.GR" ], "abstract": "Each group G of nxn permutation matrices has a corresponding permutation polytope, P(G):=conv(G) in R^{nxn}. We relate the structure of P(G) to the transitivity of G. In particular, we show that if G has t nontrivial orbits, then min{2t,floor(n/2)} is a sharp upper bound on the diameter of the graph of P(G); so if G is transitive, the diameter is at most 2. We also show that P(G) achieves its maximal dimension of (n-1)^2 precisely when G is 2-transitive. We then extend results of I. Pak on mixing times for a random walk on P(G). Our work depends on a new result for permutation groups involving writing permutations as products of indecomposable permutations.", "revisions": [ { "version": "v2", "updated": "2005-11-24T17:03:32.000Z" } ], "analyses": { "keywords": [ "permutation groups", "indecomposable elements", "nxn permutation matrices", "sharp upper bound", "work depends" ], "note": { "typesetting": "TeX", "pages": 18, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2005math......3015G" } } }