LOW-DEGREE BOOLEAN FUNCTIONS ON $S_{n}$ , WITH AN APPLICATION TO ISOPERIMETRY

We prove that Boolean functions on $S_{n}$ , whose Fourier transform is highly concentrated on irreducible representations indexed by partitions of...

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Main Authors: DAVID ELLIS, YUVAL FILMUS, EHUD FRIEDGUT
Format: Article
Language:English
Published: Cambridge University Press 2017-01-01
Series:Forum of Mathematics, Sigma
Subjects:
Online Access:https://www.cambridge.org/core/product/identifier/S205050941700024X/type/journal_article
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author DAVID ELLIS
YUVAL FILMUS
EHUD FRIEDGUT
author_facet DAVID ELLIS
YUVAL FILMUS
EHUD FRIEDGUT
author_sort DAVID ELLIS
collection DOAJ
description We prove that Boolean functions on $S_{n}$ , whose Fourier transform is highly concentrated on irreducible representations indexed by partitions of $n$ whose largest part has size at least $n-t$ , are close to being unions of cosets of stabilizers of $t$ -tuples. We also obtain an edge-isoperimetric inequality for the transposition graph on $S_{n}$ which is asymptotically sharp for subsets of $S_{n}$ of size $n!/\text{poly}(n)$ , using eigenvalue techniques. We then combine these two results to obtain a sharp edge-isoperimetric inequality for subsets of $S_{n}$ of size $(n-t)!$ , where $n$ is large compared to $t$ , confirming a conjecture of Ben Efraim in these cases.
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spelling doaj.art-629f3998f4b94fda8b5c53d0e32fdaac2023-03-09T12:34:43ZengCambridge University PressForum of Mathematics, Sigma2050-50942017-01-01510.1017/fms.2017.24LOW-DEGREE BOOLEAN FUNCTIONS ON $S_{n}$ , WITH AN APPLICATION TO ISOPERIMETRYDAVID ELLIS0YUVAL FILMUS1EHUD FRIEDGUT2School of Mathematical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK;Computer Science Department, Technion – Israel Institute of Technology, Technion City, Haifa 3200003, Israel;Faculty of Mathematics and Computer Science, Weizmann Institute of Science, Rehovot 76100, Israel;We prove that Boolean functions on $S_{n}$ , whose Fourier transform is highly concentrated on irreducible representations indexed by partitions of $n$ whose largest part has size at least $n-t$ , are close to being unions of cosets of stabilizers of $t$ -tuples. We also obtain an edge-isoperimetric inequality for the transposition graph on $S_{n}$ which is asymptotically sharp for subsets of $S_{n}$ of size $n!/\text{poly}(n)$ , using eigenvalue techniques. We then combine these two results to obtain a sharp edge-isoperimetric inequality for subsets of $S_{n}$ of size $(n-t)!$ , where $n$ is large compared to $t$ , confirming a conjecture of Ben Efraim in these cases.https://www.cambridge.org/core/product/identifier/S205050941700024X/type/journal_article05D05
spellingShingle DAVID ELLIS
YUVAL FILMUS
EHUD FRIEDGUT
LOW-DEGREE BOOLEAN FUNCTIONS ON $S_{n}$ , WITH AN APPLICATION TO ISOPERIMETRY
Forum of Mathematics, Sigma
05D05
title LOW-DEGREE BOOLEAN FUNCTIONS ON $S_{n}$ , WITH AN APPLICATION TO ISOPERIMETRY
title_full LOW-DEGREE BOOLEAN FUNCTIONS ON $S_{n}$ , WITH AN APPLICATION TO ISOPERIMETRY
title_fullStr LOW-DEGREE BOOLEAN FUNCTIONS ON $S_{n}$ , WITH AN APPLICATION TO ISOPERIMETRY
title_full_unstemmed LOW-DEGREE BOOLEAN FUNCTIONS ON $S_{n}$ , WITH AN APPLICATION TO ISOPERIMETRY
title_short LOW-DEGREE BOOLEAN FUNCTIONS ON $S_{n}$ , WITH AN APPLICATION TO ISOPERIMETRY
title_sort low degree boolean functions on s n with an application to isoperimetry
topic 05D05
url https://www.cambridge.org/core/product/identifier/S205050941700024X/type/journal_article
work_keys_str_mv AT davidellis lowdegreebooleanfunctionsonsnwithanapplicationtoisoperimetry
AT yuvalfilmus lowdegreebooleanfunctionsonsnwithanapplicationtoisoperimetry
AT ehudfriedgut lowdegreebooleanfunctionsonsnwithanapplicationtoisoperimetry