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PRODID:-//Discrete Mathematics Group - ECPv6.15.20//NONSGML v1.0//EN
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X-WR-CALDESC:Events for Discrete Mathematics Group
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TZID:Asia/Seoul
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TZOFFSETFROM:+0900
TZOFFSETTO:+0900
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DTSTART:20180101T000000
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BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20191121T163000
DTEND;TZID=Asia/Seoul:20191121T173000
DTSTAMP:20260420T184343
CREATED:20191028T154322Z
LAST-MODIFIED:20240707T084339Z
UID:1641-1574353800-1574357400@dimag.ibs.re.kr
SUMMARY:Frédéric Meunier\, Topological bounds for graph representations over any field
DESCRIPTION:Haviv (European Journal of Combinatorics\, 2019) has recently proved that some topological lower bounds on the chromatic number of graphs are also lower bounds on their orthogonality dimension over $\mathbb {R}$. We show that this holds actually for all known topological lower bounds and all fields. We also improve the topological bound he obtained for the minrank parameter over $\mathbb {R}$ – an important graph invariant from coding theory – and show that this bound is actually valid for all fields as well. The notion of independent representation over a matroid is introduced and used in a general theorem having these results as corollaries. Related complexity results are also discussed.\nThis is joint work with Meysam Alishahi.
URL:https://dimag.ibs.re.kr/event/2019-11-21/
LOCATION:Room B232\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
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