{ "id": "1701.04321", "version": "v1", "published": "2017-01-16T15:16:15.000Z", "updated": "2017-01-16T15:16:15.000Z", "title": "Proof of an entropy conjecture of Leighton and Moitra", "authors": [ "Hüseyin Acan", "Pat Devlin", "Jeff Kahn" ], "comment": "9 pages", "categories": [ "math.CO" ], "abstract": "We prove the following conjecture of Leighton and Moitra. Let $T$ be a tournament on $[n]$ and $S_n$ the set of permutations of $[n]$. For an arc $uv$ of $T$, let $A_{uv}=\\{\\sigma \\in S_n \\, : \\, \\sigma(u)<\\sigma(v) \\}$. $\\textbf{Theorem.}$ For a fixed $\\varepsilon>0$, if $\\mathbb{P}$ is a probability distribution on $S_n$ such that $\\mathbb{P}(A_{uv})>1/2+\\varepsilon$ for every arc $uv$ of $T$, then the binary entropy of $\\mathbb{P}$ is at most $(1-\\vartheta_{\\varepsilon})\\log_2 n!$ for some (fixed) positive $\\vartheta_\\varepsilon$.", "revisions": [ { "version": "v1", "updated": "2017-01-16T15:16:15.000Z" } ], "analyses": { "subjects": [ "05C20", "05D40", "94A17", "06A07" ], "keywords": [ "entropy conjecture", "probability distribution", "binary entropy" ], "note": { "typesetting": "TeX", "pages": 9, "language": "en", "license": "arXiv", "status": "editable" } } }