BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Discrete Mathematics Group - ECPv5.1.6//NONSGML v1.0//EN
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-WR-CALNAME:Discrete Mathematics Group
X-ORIGINAL-URL:https://dimag.ibs.re.kr
X-WR-CALDESC:Events for Discrete Mathematics Group
BEGIN:VTIMEZONE
TZID:Asia/Seoul
BEGIN:STANDARD
TZOFFSETFROM:+0900
TZOFFSETTO:+0900
TZNAME:KST
DTSTART:20200101T000000
END:STANDARD
END:VTIMEZONE
BEGIN:VEVENT
DTSTART;VALUE=DATE:20210614
DTEND;VALUE=DATE:20210619
DTSTAMP:20200920T010226
CREATED:20190607T162650Z
LAST-MODIFIED:20200914T072532Z
UID:947-1623628800-1624060799@dimag.ibs.re.kr
SUMMARY:Seymour is Seventy
DESCRIPTION:A conference honouring the seventieth birthday of Paul Seymour \n\nTo be held in ENS de Lyon\, France\, June 15 – 19\, 2020. \nDue to the COVID-19\, we have postponed the conference to June 14-18\, 2021 tentatively. The final decision will be made at the beginning of 2021. \nConference Website: https://dimag.ibs.re.kr/seymour70/ \nSponsors: \n\nIBS Discrete Mathematics Group.\nLIP\, ENS de Lyon\, France.\nDepartment of Mathematics\, Princeton University.
URL:https://dimag.ibs.re.kr/event/seymour-is-seventy/
LOCATION:ENS de Lyon\, Lyon\, France
CATEGORIES:Workshops and Conferences
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20201105T100000
DTEND;TZID=Asia/Seoul:20201105T110000
DTSTAMP:20200920T010226
CREATED:20200818T142112Z
LAST-MODIFIED:20200818T142112Z
UID:2820-1604570400-1604574000@dimag.ibs.re.kr
SUMMARY:Daniel Cranston\, Vertex Partitions into an Independent Set and a Forest with Each Component Small
DESCRIPTION:For each integer $k\ge 2$\, we determine a sharp bound on\n$\operatorname{mad}(G)$ such that $V(G)$ can be partitioned into sets $I$ and $F_k$\, where $I$ is an independent set and $G[F_k]$ is a forest in which each component has at most k vertices. For each $k$ we construct an infinite family of examples showing our result is best possible. Hendrey\, Norin\, and Wood asked for the largest function $g(a\,b)$ such that if $\operatorname{mad}(G) < g(a\,b)$ then $V(G)$ has a partition into sets $A$ and $B$ such that $\operatorname{mad}(G[A]) < a$ and $\operatorname{mad}(G[B]) < b$. They specifically asked for the value of $g(1\,b)$\, which corresponds to the case that $A$ is an independent set. Previously\, the only values known were $g(1\,4/3)$ and $g(1\,2)$. We find the value of $g(1\,b)$ whenever $4/3 < b < 2$. This is joint work with Matthew Yancey.
URL:https://dimag.ibs.re.kr/event/2020-11-05/
LOCATION:Zoom
CATEGORIES:Virtual Discrete Math Colloquium
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20201015T170000
DTEND;TZID=Asia/Seoul:20201015T180000
DTSTAMP:20200920T010226
CREATED:20200915T062234Z
LAST-MODIFIED:20200915T062234Z
UID:2982-1602781200-1602784800@dimag.ibs.re.kr
SUMMARY:Hong Liu (刘鸿)\, Cycles and trees in graphs (8/8)
DESCRIPTION:This lecture series covers several different techniques on embedding paths/trees/cycles in (pseudo)random graphs/expanders as (induced) subgraphs. \nZoom ID : 8628398170 Password : 123450
URL:https://dimag.ibs.re.kr/event/2020-10-15/
LOCATION:Zoom
CATEGORIES:Online Lecture Series
ORGANIZER;CN="Jaehoon%20Kim%20%28%EA%B9%80%EC%9E%AC%ED%9B%88%29":MAILTO:https://sites.google.com/view/jaehoon-kim
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20201014T170000
DTEND;TZID=Asia/Seoul:20201014T180000
DTSTAMP:20200920T010226
CREATED:20200915T062130Z
LAST-MODIFIED:20200915T062306Z
UID:2980-1602694800-1602698400@dimag.ibs.re.kr
SUMMARY:Hong Liu (刘鸿)\, Cycles and trees in graphs (7/8)
DESCRIPTION:This lecture series covers several different techniques on embedding paths/trees/cycles in (pseudo)random graphs/expanders as (induced) subgraphs. \nZoom ID : 8628398170 Password : 123450
URL:https://dimag.ibs.re.kr/event/2020-10-14/
LOCATION:Zoom
CATEGORIES:Online Lecture Series
ORGANIZER;CN="Jaehoon%20Kim%20%28%EA%B9%80%EC%9E%AC%ED%9B%88%29":MAILTO:https://sites.google.com/view/jaehoon-kim
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20201013T170000
DTEND;TZID=Asia/Seoul:20201013T180000
DTSTAMP:20200920T010226
CREATED:20200915T062032Z
LAST-MODIFIED:20200915T062032Z
UID:2978-1602608400-1602612000@dimag.ibs.re.kr
SUMMARY:Hong Liu (刘鸿)\, Cycles and trees in graphs (6/8)
DESCRIPTION:This lecture series covers several different techniques on embedding paths/trees/cycles in (pseudo)random graphs/expanders as (induced) subgraphs. \nZoom ID : 8628398170 Password : 123450
URL:https://dimag.ibs.re.kr/event/2020-10-13/
LOCATION:Zoom
CATEGORIES:Online Lecture Series
ORGANIZER;CN="Jaehoon%20Kim%20%28%EA%B9%80%EC%9E%AC%ED%9B%88%29":MAILTO:https://sites.google.com/view/jaehoon-kim
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20201012T170000
DTEND;TZID=Asia/Seoul:20201012T180000
DTSTAMP:20200920T010226
CREATED:20200915T061926Z
LAST-MODIFIED:20200915T062029Z
UID:2976-1602522000-1602525600@dimag.ibs.re.kr
SUMMARY:Hong Liu (刘鸿)\, Cycles and trees in graphs (5/8)
DESCRIPTION:This lecture series covers several different techniques on embedding paths/trees/cycles in (pseudo)random graphs/expanders as (induced) subgraphs. \nZoom ID : 8628398170 Password : 123450
URL:https://dimag.ibs.re.kr/event/2020-10-12/
LOCATION:Zoom
CATEGORIES:Online Lecture Series
ORGANIZER;CN="Jaehoon%20Kim%20%28%EA%B9%80%EC%9E%AC%ED%9B%88%29":MAILTO:https://sites.google.com/view/jaehoon-kim
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20201008T170000
DTEND;TZID=Asia/Seoul:20201008T180000
DTSTAMP:20200920T010226
CREATED:20200915T061756Z
LAST-MODIFIED:20200915T061826Z
UID:2974-1602176400-1602180000@dimag.ibs.re.kr
SUMMARY:Hong Liu (刘鸿)\, Cycles and trees in graphs (4/8)
DESCRIPTION:This lecture series covers several different techniques on embedding paths/trees/cycles in (pseudo)random graphs/expanders as (induced) subgraphs. \nZoom ID : 8628398170 Password : 123450
URL:https://dimag.ibs.re.kr/event/2020-10-08/
LOCATION:Zoom
CATEGORIES:Online Lecture Series
ORGANIZER;CN="Jaehoon%20Kim%20%28%EA%B9%80%EC%9E%AC%ED%9B%88%29":MAILTO:https://sites.google.com/view/jaehoon-kim
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20201007T170000
DTEND;TZID=Asia/Seoul:20201007T180000
DTSTAMP:20200920T010226
CREATED:20200915T061653Z
LAST-MODIFIED:20200915T061843Z
UID:2971-1602090000-1602093600@dimag.ibs.re.kr
SUMMARY:Hong Liu (刘鸿)\, Cycles and trees in graphs (3/8)
DESCRIPTION:This lecture series covers several different techniques on embedding paths/trees/cycles in (pseudo)random graphs/expanders as (induced) subgraphs. \nZoom ID : 8628398170 Password : 123450
URL:https://dimag.ibs.re.kr/event/2020-10-07/
LOCATION:Zoom
CATEGORIES:Online Lecture Series
ORGANIZER;CN="Jaehoon%20Kim%20%28%EA%B9%80%EC%9E%AC%ED%9B%88%29":MAILTO:https://sites.google.com/view/jaehoon-kim
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20201006T170000
DTEND;TZID=Asia/Seoul:20201006T180000
DTSTAMP:20200920T010226
CREATED:20200915T060857Z
LAST-MODIFIED:20200915T060857Z
UID:2969-1602003600-1602007200@dimag.ibs.re.kr
SUMMARY:Hong Liu (刘鸿)\, Cycles and trees in graphs (2/8)
DESCRIPTION:This lecture series covers several different techniques on embedding paths/trees/cycles in (pseudo)random graphs/expanders as (induced) subgraphs. \nZoom ID : 8628398170 Password : 123450
URL:https://dimag.ibs.re.kr/event/2020-10-06/
LOCATION:Zoom
CATEGORIES:Online Lecture Series
ORGANIZER;CN="Jaehoon%20Kim%20%28%EA%B9%80%EC%9E%AC%ED%9B%88%29":MAILTO:https://sites.google.com/view/jaehoon-kim
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20201005T170000
DTEND;TZID=Asia/Seoul:20201005T180000
DTSTAMP:20200920T010226
CREATED:20200915T060706Z
LAST-MODIFIED:20200915T060859Z
UID:2967-1601917200-1601920800@dimag.ibs.re.kr
SUMMARY:Hong Liu (刘鸿)\, Cycles and trees in graphs (1/8)
DESCRIPTION:This lecture series covers several different techniques on embedding paths/trees/cycles in (pseudo)random graphs/expanders as (induced) subgraphs. \nZoom ID : 8628398170 Password : 123450
URL:https://dimag.ibs.re.kr/event/2020-10-05/
LOCATION:Zoom
CATEGORIES:Online Lecture Series
ORGANIZER;CN="Jaehoon%20Kim%20%28%EA%B9%80%EC%9E%AC%ED%9B%88%29":MAILTO:https://sites.google.com/view/jaehoon-kim
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20200924T100000
DTEND;TZID=Asia/Seoul:20200924T110000
DTSTAMP:20200920T010226
CREATED:20200811T231744Z
LAST-MODIFIED:20200811T231827Z
UID:2781-1600941600-1600945200@dimag.ibs.re.kr
SUMMARY:Zihan Tan\, Towards Tight(er) Bounds for the Excluded Grid Theorem
DESCRIPTION:We study the Excluded Grid Theorem\, a fundamental structural result in graph theory\, that was proved by Robertson and Seymour in their seminal work on graph minors. The theorem states that there is a function $f$\, such that for every integer $g > 0$\, every graph of treewidth at least $f(g)$ contains the g×g-grid as a minor. For every integer $g > 0$\, let $f(g)$ be the smallest value for which the theorem holds. Establishing tight bounds on $f(g)$ is an important graph-theoretic question. Robertson and Seymour showed that f(g) is at least of order $g^2 \log g$. For a long time\, the best known upper bounds on $f(g)$ were super-exponential in $g$. The first polynomial upper bound of $f(g) = O(g^{98} \operatorname{poly log} g)$ was proved by Chekuri and Chuzhoy. It was later improved to $f(g) = O(g^{36} \operatorname{poly log} g)$\, and then to $f(g) = O(g^{19} \operatorname{poly log} g)$. In this talk\, we present our recent work that further improves this bound to $f(g) = O(g^9 \operatorname{poly log} g)$ via a simpler proof. Moreover\, while there are natural barriers that seem to prevent the previous methods from yielding tight bounds for the theorem\, it seems conceivable that the techniques proposed in this talk can lead to even tighter bounds on $f(g)$. \nThis talk is based on joint work with Julia Chuzhoy.
URL:https://dimag.ibs.re.kr/event/2020-09-24/
LOCATION:Zoom
CATEGORIES:Virtual Discrete Math Colloquium
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20200922T163000
DTEND;TZID=Asia/Seoul:20200922T173000
DTSTAMP:20200920T010226
CREATED:20200914T065243Z
LAST-MODIFIED:20200914T065243Z
UID:2960-1600792200-1600795800@dimag.ibs.re.kr
SUMMARY:Jinha Kim (김진하)\, Collapsibility of Non-Cover Complexes of Graphs
DESCRIPTION:Let $G$ be a graph on the vertex set $V$. A vertex subset $W \subset V$ is a cover of $G$ if $V \setminus W$ is an independent set of $G$\, and $W$ is a non-cover of $G$ if $W$ is not a cover of $G$. The non-cover complex of $G$ is a simplicial complex on $V$ whose faces are non-covers of $G$. Then the non-cover complex of $G$ is the combinatorial Alexander dual of the independence complex of $G$. In this talk\, I will show the $(|V(G)|-i\gamma(G)-1)$-collapsibility of the non-cover complex of a graph $G$ where $i\gamma(G)$ denotes the independence domination number of $G$ using the minimal exclusion sequence method. This is joint work with Ilkyoo Choi and Boram Park.
URL:https://dimag.ibs.re.kr/event/2020-09-22/
LOCATION:Room B232\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
END:VEVENT
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