BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Discrete Mathematics Group - ECPv6.15.20//NONSGML v1.0//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-ORIGINAL-URL:https://dimag.ibs.re.kr
X-WR-CALDESC:Events for Discrete Mathematics Group
REFRESH-INTERVAL;VALUE=DURATION:PT1H
X-Robots-Tag:noindex
X-PUBLISHED-TTL:PT1H
BEGIN:VTIMEZONE
TZID:Asia/Seoul
BEGIN:STANDARD
TZOFFSETFROM:+0900
TZOFFSETTO:+0900
TZNAME:KST
DTSTART:20240101T000000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250304T163000
DTEND;TZID=Asia/Seoul:20250304T173000
DTSTAMP:20260417T014153
CREATED:20250123T112518Z
LAST-MODIFIED:20250223T142525Z
UID:10492-1741105800-1741109400@dimag.ibs.re.kr
SUMMARY:Irene Muzi\, An elementary bound for Younger's conjecture
DESCRIPTION:In 1996\, Reed\, Robertson\, Seymour and Thomas proved Younger’s Conjecture\, which states that for all directed graphs D\, there exists a function f such that if D does not contain k disjoint cycles\, D contains a feedback vertex set\, i.e. a subset of vertices whose deletion renders the graph acyclic\, of size bounded by f(k). However\, the function obtained by Reed\, Robertson\, Seymour and Thomas is enormous and\, in fact\, not even elementary. The bound had\, so far\, not been improved. In this talk\, I will present new techniques to improve the bound from non-elementary to elementary. This is joint work with Meike Hatzel\, Stephan Kreutzer and Marcelo Milani.
URL:https://dimag.ibs.re.kr/event/2025-03-04/
LOCATION:Room B332\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250311T163000
DTEND;TZID=Asia/Seoul:20250311T173000
DTSTAMP:20260417T014154
CREATED:20240909T194937Z
LAST-MODIFIED:20250218T150344Z
UID:9870-1741710600-1741714200@dimag.ibs.re.kr
SUMMARY:Johannes Carmesin\, Open problems in graph theory
DESCRIPTION:Since the proof of the graph minor structure theorem by Robertson and Seymour in 2004\, its underlying ideas have found applications in a much broader range of settings than their original context. They have driven profound progress in areas such as vertex minors\, pivot minors\, matroids\, directed graphs\, and 2-dimensional simplicial complexes. In this talk\, I will present three open problems related to this development\, each requiring some background.
URL:https://dimag.ibs.re.kr/event/2025-03-11/
LOCATION:Room B332\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20250318T163000
DTEND;TZID=Asia/Seoul:20250318T173000
DTSTAMP:20260417T014154
CREATED:20250205T073256Z
LAST-MODIFIED:20250305T204931Z
UID:10539-1742315400-1742319000@dimag.ibs.re.kr
SUMMARY:Michał Seweryn\, Dimension and standard examples in planar posets
DESCRIPTION:The dimension of a poset is the least integer $d$ such that the poset is isomorphic to a subposet of the product of $d$ linear orders. In 1983\, Kelly constructed planar posets of arbitrarily large dimension. Crucially\, the posets in his construction involve large standard examples\, the canonical structure preventing a poset from having small dimension. Kelly’s construction inspired one of the most challenging questions in dimension theory: are large standard examples unavoidable in planar posets of large dimension? We answer the question affirmatively by proving that every $d$-dimensional planar poset contains a standard example of order $\Omega(d)$. More generally\, we prove that every poset from Kelly’s construction appears in every poset with a planar cover graph of sufficiently large dimension. \njoint work with Heather Smith Blake\, Jędrzej Hodor\, Piotr Micek\, and William T. Trotter.
URL:https://dimag.ibs.re.kr/event/2025-03-18/
LOCATION:Room B332\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
END:VEVENT
END:VCALENDAR