BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Discrete Mathematics Group - ECPv5.1.2//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
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END:VTIMEZONE
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200824
DTEND;VALUE=DATE:20200829
DTSTAMP:20200602T021734
CREATED:20191122T084127Z
LAST-MODIFIED:20200427T082500Z
UID:1878-1598227200-1598659199@dimag.ibs.re.kr
SUMMARY:2020 IBS Workshop on Extremal and Probabilistic Combinatorics (postponed)
DESCRIPTION:Date\nAugust 24\, 2020 – August 28\, 2020 \nArrival: August 23 Sunday. Departure: August 29\, Saturday \nVenue\nInstitute for Basic Science\, 55 Expo-ro\, Yuseong-gu\, Daejeon\, South Korea \nInvited Speakers\n\nJulia Böttcher\, London School of Economics\nBoris Bukh\, Carnegie Mellon University\nAmin Coja-Oghlan\, Goethe University\nDavid Conlon\, Caltech\nPenny Haxell\, University of Waterloo\nHao Huang\, Emory University\nJeff Kahn\, Rutgers University\nAlexandr V. Kostochka\, University of Illinois at Urbana-Champaign\nMichael Krivelevich\, Tel-Aviv University\nMichał Karoński\, Adam Mickiewicz University in Poznań\nAnita Liebenau\, UNSW Sydney\nHong Liu\, University of Warwick\nTomasz Łuczak\, Adam Mickiewicz University in Poznań\nRichard Montgomery\, University of Birmingham\nTobias Müller\, Groningen University\nPéter Pál Pach\, Budapest University of Technology and Economics\nMathias Schacht\, University of Hamburg\nAsaf Shapira\, Tel-Aviv University\nJoel Spencer\, New York University\nVan Vu\, Yale University\nYufei Zhao\, MIT\nThis list is incomplete. It is subject to change.\n\nAccommodation\nLotte City Hotel and Hotel ICC are within 700m. Invited speakers will be provided an accommodation at the near-by hotels. \nOrganizers\n\nMihyun Kang\, Graz University of Technology\, Austria.\nJaehoon Kim\, KAIST\, Korea.\nSang-il Oum\, IBS Discrete Mathematics Group\, Korea and KAIST\, Korea.\n\n
URL:https://dimag.ibs.re.kr/event/2020-ibs-workshop/
LOCATION:Room B234\, IBS (기초과학연구원)
CATEGORIES:Workshops and Conferences
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200810
DTEND;VALUE=DATE:20200814
DTSTAMP:20200602T021734
CREATED:20200221T012853Z
LAST-MODIFIED:20200427T014651Z
UID:2145-1597017600-1597363199@dimag.ibs.re.kr
SUMMARY:Nonlinear Algebra in Daejeon (Postponed)
DESCRIPTION:Program\n\nSummer School @ KAIST (August 4-7\, 2020)\nDiscussion Weekend (August 8-9\, 2020)\nWorkshop @ IBS Science Culture Center (August 10-13\, 2020)\n\nWebsite: https://dimag.ibs.re.kr/home/nonlinear/ \nOrganizing Committee\n\nInsong Choe (Konkuk U.)\nKangjin Han (DGIST)\nDavid Hyeon (SNU)\nSijong Kwak (KAIST)\nYongnam Lee (KAIST)\nAnton Leykin (Georgia Tech)\nSang-il Oum (IBS & KAIST)\nFrank Sottile (TAMU)\n\n
URL:https://dimag.ibs.re.kr/event/nonlinear-algebra-in-daejeon/
LOCATION:IBS Science Culture Center
CATEGORIES:Workshops and Conferences
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20200721T163000
DTEND;TZID=Asia/Seoul:20200721T173000
DTSTAMP:20200602T021734
CREATED:20200519T123058Z
LAST-MODIFIED:20200519T123222Z
UID:2456-1595349000-1595352600@dimag.ibs.re.kr
SUMMARY:Ilkyoo Choi (최일규)\, Flexibility of Planar Graphs
DESCRIPTION:Oftentimes in chromatic graph theory\, precoloring techniques are utilized in order to obtain the desired coloring result. For example\, Thomassen’s proof for 5-choosability of planar graphs actually shows that two adjacent vertices on the same face can be precolored. In this vein\, we investigate a precoloring extension problem formalized by Dvorak\, Norin\, and Postle named flexibility. Given a list assignment $L$ on a graph $G$\, an $L$-request is a function on a subset $S$ of the vertices that indicates a preferred color in $L(v)$ for each vertex $v\in S$. A graph $G$ is $\varepsilon$-flexible for list size $k$ if given a $k$-list assignment $L$ and an $L$-request\, there is an $L$-coloring of $G$ satisfying an $\varepsilon$-fraction of the requests in $S$. We survey known results regarding this new concept\, and prove some new results regarding flexibility of planar graphs. \n
URL:https://dimag.ibs.re.kr/event/2020-07-21/
LOCATION:Room B232\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20200707T163000
DTEND;TZID=Asia/Seoul:20200707T173000
DTSTAMP:20200602T021734
CREATED:20200526T020628Z
LAST-MODIFIED:20200526T020628Z
UID:2481-1594139400-1594143000@dimag.ibs.re.kr
SUMMARY:Seog-Jin Kim (김석진)\, Online DP-coloring of graphs
DESCRIPTION:Online list coloring and DP-coloring are generalizations of list coloring that attracted considerable attention recently. Each of the paint number\, $\chi_P(G)$\, (the minimum number of colors needed for an online coloring of $G$) and the DP-chromatic number\, $\chi_{DP}(G)$\, (the minimum number of colors needed for a DP-coloring of $G$) is at least the list chromatic number\, $\chi_\ell(G)$\, of $G$ and can be much larger. On the other hand\, each of them has a number of useful properties.\nWe introduce a common generalization\, online DP-coloring\, of online list coloring and DP-coloring and to study its properties. This is joint work with Alexandr Kostochka\, Xuer Li\, and Xuding Zhu. \n
URL:https://dimag.ibs.re.kr/event/2020-07-07/
LOCATION:Room B232\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20200616T163000
DTEND;TZID=Asia/Seoul:20200616T173000
DTSTAMP:20200602T021734
CREATED:20200525T080845Z
LAST-MODIFIED:20200525T080845Z
UID:2478-1592325000-1592328600@dimag.ibs.re.kr
SUMMARY:Andreas Holmsen\, Fractional Helly and topological complexity
DESCRIPTION:The fractional Helly theorem is a simple yet remarkable generalization of Helly’s classical theorem on the intersection of convex sets\, and it is of considerable interest to extend the fractional Helly theorem beyond the setting of convexity. In this talk I will discuss a recent result which shows that the fractional Helly theorem holds for families of subsets of $\mathbb R^d$ which satisfy only very weak topological assumptions. The proofs combine a number of tools such as homological minors\, stair-convexity\, supersaturation in hypergraphs\, Radon dimension\, and Ramsey-type arguments. This is joint work with Xavier Goaoc and Zuzana Patáková. \n
URL:https://dimag.ibs.re.kr/event/2020-06-16/
LOCATION:Room B232\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20200615
DTEND;VALUE=DATE:20200620
DTSTAMP:20200602T021734
CREATED:20190607T162650Z
LAST-MODIFIED:20200408T072212Z
UID:947-1592179200-1592611199@dimag.ibs.re.kr
SUMMARY:Seymour is Seventy (postponed)
DESCRIPTION:A conference honouring the seventieth birthday of Paul Seymour \n\nTo be held in ENS de Lyon\, France\, June 15 – 19\, 2020 \nConference Website: https://dimag.ibs.re.kr/seymour70/ \nSponsors: \n\nIBS Discrete Mathematics Group.\nLIP\, ENS de Lyon\, France.\nDepartment of Mathematics\, Princeton University.\n\n\n
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:20200609T163000
DTEND;TZID=Asia/Seoul:20200609T173000
DTSTAMP:20200602T021734
CREATED:20200529T052601Z
LAST-MODIFIED:20200529T052615Z
UID:2498-1591720200-1591723800@dimag.ibs.re.kr
SUMMARY:Jiseung Kim (김지승)\, Hardness and concrete security in cryptography
DESCRIPTION:Computationally hard problems have been widely used to construct cryptographic primitives such as encryptions\, digital signatures. For example\, provably secure primitives are based on a reduction from the hardness problems. However\, the concrete instantiation of primitives does not follow the results of hardness problems due to its efficiency. In this talk\, we introduce cryptographic hardness problems widely used in cryptography and the gap between hardness results and concrete security of cryptographic primitives based on our recent works. \n
URL:https://dimag.ibs.re.kr/event/2020-06-09/
LOCATION:Room B232\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20200602T163000
DTEND;TZID=Asia/Seoul:20200602T173000
DTSTAMP:20200602T021734
CREATED:20200528T061536Z
LAST-MODIFIED:20200528T061632Z
UID:2491-1591115400-1591119000@dimag.ibs.re.kr
SUMMARY:Huy-Tung Nguyen\, The average cut-rank of graphs
DESCRIPTION:The cut-rank of a set X of vertices in a graph G is defined as the rank of the X×(V(G)∖X) matrix over the binary field whose (i\,j)-entry is 1 if the vertex i in X is adjacent to the vertex j in V(G)∖X and 0 otherwise. We introduce the graph parameter called the average cut-rank of a graph\, defined as the expected value of the cut-rank of a random set of vertices. We show that this parameter does not increase when taking vertex-minors of graphs and a class of graphs has bounded average cut-rank if and only if it has bounded neighborhood diversity. This allows us to deduce that for each real α\, the list of induced-subgraph-minimal graphs having average cut-rank larger than (or at least) α is finite. We further refine this by providing an upper bound on the size of obstruction and a lower bound on the number of obstructions for average cut-rank at most (or smaller than) α for each real α≥0. Finally\, we describe explicitly all graphs of average cut-rank at most 3/2 and determine up to 3/2 all possible values that can be realized as the average cut-rank of some graph. This is joint work with Sang-il Oum. \n
URL:https://dimag.ibs.re.kr/event/2020-06-02/
LOCATION:Room B232\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
END:VEVENT
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