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PRODID:-//Discrete Mathematics Group - ECPv6.15.20//NONSGML v1.0//EN
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X-WR-CALNAME:Discrete Mathematics Group
X-ORIGINAL-URL:https://dimag.ibs.re.kr
X-WR-CALDESC:Events for Discrete Mathematics Group
REFRESH-INTERVAL;VALUE=DURATION:PT1H
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BEGIN:VTIMEZONE
TZID:Asia/Seoul
BEGIN:STANDARD
TZOFFSETFROM:+0900
TZOFFSETTO:+0900
TZNAME:KST
DTSTART:20230101T000000
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END:VTIMEZONE
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20240702T163000
DTEND;TZID=Asia/Seoul:20240702T173000
DTSTAMP:20260417T234117
CREATED:20240403T041848Z
LAST-MODIFIED:20240705T153033Z
UID:8483-1719937800-1719941400@dimag.ibs.re.kr
SUMMARY:Kisun Lee (이기선)\, Symmetric Tropical Rank 2 Matrices
DESCRIPTION:Tropical geometry replaces usual addition and multiplication with tropical addition (the min) and tropical multiplication (the sum)\, which offers a polyhedral interpretation of algebraic variety. This talk aims to pitch the usefulness of tropical geometry in understanding classical algebraic geometry. As an example\, we introduce the tropicalization of the variety of symmetric rank 2 matrices. We discuss that this tropicalization has a simplicial complex structure as the space of symmetric bicolored trees. As a result\, we show that this space is shellable and delve into its matroidal structure. It is based on the joint work with May Cai and Josephine Yu.
URL:https://dimag.ibs.re.kr/event/2024-07-02/
LOCATION:Room B332\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
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BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20240705T163000
DTEND;TZID=Asia/Seoul:20240705T173000
DTSTAMP:20260417T234117
CREATED:20240613T134309Z
LAST-MODIFIED:20240705T152046Z
UID:8763-1720197000-1720200600@dimag.ibs.re.kr
SUMMARY:Hyunwoo Lee (이현우)\, Random matchings in linear hypergraphs
DESCRIPTION:For a given hypergraph $H$ and a vertex $v\in V(H)$\, consider a random matching $M$ chosen uniformly from the set of all matchings in $H.$ In $1995\,$ Kahn conjectured that if $H$ is a $d$-regular linear $k$-uniform hypergraph\, the probability that $M$ does not cover $v$ is $(1 + o_d(1))d^{-1/k}$ for all vertices $v\in V(H)$. This conjecture was proved for $k = 2$ by Kahn and Kim in 1998. In this paper\, we disprove this conjecture for all $k \geq 3.$ For infinitely many values of $d\,$ we construct $d$-regular linear $k$-uniform hypergraph $H$ containing two vertices $v_1$ and $v_2$ such that $\mathcal{P}(v_1 \notin M) = 1 – \frac{(1 + o_d(1))}{d^{k-2}}$ and $\mathcal{P}(v_2 \notin M) = \frac{(1 + o_d(1))}{d+1}.$ The gap between $\mathcal{P}(v_1 \notin M)$ and $\mathcal{P}(v_2 \notin M)$ in this $H$ is best possible. In the course of proving this\, we also prove a hypergraph analog of Godsil’s result on matching polynomials and paths in graphs\, which is of independent interest.
URL:https://dimag.ibs.re.kr/event/2024-07-05/
LOCATION:Room B332\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20240715
DTEND;VALUE=DATE:20240720
DTSTAMP:20260417T234117
CREATED:20231122T060655Z
LAST-MODIFIED:20240705T155117Z
UID:7939-1721001600-1721433599@dimag.ibs.re.kr
SUMMARY:IBS-DIMAG workshop on combinatorics and geometric measure theory
DESCRIPTION:Website: https://cgmt.dimag.kr/ \nArrival Date: July 14\, 2024 Sunday. \nDeparture Date: July 20\, 2024 Saturday. \nOrganizers \n\nBen Lund (IBS Discrete Mathematics Group)\nDoowon Koh (Chungbuk National University)\nSang-il Oum (IBS Discrete Mathematics Group / KAIST)
URL:https://dimag.ibs.re.kr/event/2024-07-15/
LOCATION:Room B109\, IBS (기초과학연구원)
CATEGORIES:Workshops and Conferences
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BEGIN:VEVENT
DTSTART;VALUE=DATE:20240722
DTEND;VALUE=DATE:20240727
DTSTAMP:20260417T234117
CREATED:20240410T044447Z
LAST-MODIFIED:20240705T153024Z
UID:8506-1721606400-1722038399@dimag.ibs.re.kr
SUMMARY:2024 Summer School on Combinatorics and Algorithms (2024 조합론 및 알고리즘 여름학교)
DESCRIPTION:The 2024 Summer School on Combinatorics and Algorithms is a venue for students and early-career researchers to learn selected topics in theoretical computer science and discrete mathematics. It will be a great opportunity for young and aspiring researchers to study topics which are important but not covered during the lectures in the university classes. This summer\, two lecture series\, combinatorial optimization and grid minor theorem\, will be given by two leading experts on the subjects. There will be exercise sessions where you form a team and solve challenging questions related to the lecture subjects. \nWebsite: https://combialgo.dimag.kr/ \nLecturers and Topics\n\nChien-Chung Huang (ENS Paris\, France): Combinatorial Optimization\n\nThis lecture (12.5h) will cover essential topics in combinatorial optimization including: Berge’s theorem\, Konig’s theorem\, Egervary’s theorem\, Karger’s min-cut algorithm and Gomory-Hu trees\, Edmonds’ blossom algorithm for maximum matching\, matroid 101\, multi-commodity flow and k-coverage problems. \n\nSebastian Wiederrecht (DIMAG-IBS\, Korea): From treewidth to grid minor theorem\n\nThis lecture (6h) will present the notion of tree decomposition\, treewidth and graph minor\, and introduce the grid minor theorem by Robertson and Seymour. Grid minor theory is deemed as one of the most important theory in modern graph theory and has many applications in algorithms design\, data structure\, logic\, etc.
URL:https://dimag.ibs.re.kr/event/2024-07-22/
LOCATION:Bldg. N1\, KAIST
CATEGORIES:Workshops and Conferences
ORGANIZER;CN="Eunjung Kim (%EA%B9%80%EC%9D%80%EC%A0%95)":MAILTO:eunjungkim78@gmail.com
END:VEVENT
BEGIN:VEVENT
DTSTART;VALUE=DATE:20240729
DTEND;VALUE=DATE:20240803
DTSTAMP:20260417T234117
CREATED:20240126T071556Z
LAST-MODIFIED:20240705T154124Z
UID:8206-1722211200-1722643199@dimag.ibs.re.kr
SUMMARY:2024 Korean Student Combinatorics Workshop (KSCW2024\, 2024 조합론 학생 워크샵)
DESCRIPTION:Venue\nGongju Hanok Vilage (공주한옥마을) \nOrganizers\n\nDonggyu Kim (김동규)\, KAIST and IBS Discrete Mathematics Group\nSeokbeom Kim (김석범)\, KAIST and IBS Discrete Mathematics Group\nSeonghyuk Im (임성혁)\, KAIST and IBS Extremal Combinatorics and Probability Group\nHyunwoo Lee (이현우)\, KAIST and IBS Extremal Combinatorics and Probability Group\n\n 
URL:https://dimag.ibs.re.kr/event/kscw2024/
LOCATION:Gongju Hanok Village\, Gongju
CATEGORIES:Workshops and Conferences
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20240730T163000
DTEND;TZID=Asia/Seoul:20240730T173000
DTSTAMP:20260417T234117
CREATED:20240417T003214Z
LAST-MODIFIED:20240705T153017Z
UID:8532-1722357000-1722360600@dimag.ibs.re.kr
SUMMARY:Euiwoong Lee (이의웅)\, Parameterized Approximability of F-Deletion Problems
DESCRIPTION:For a family F of graphs\, the F-Deletion Problem asks to remove the minimum number of vertices from a given graph G to ensure that G belongs to F. One of the most common ways to obtain an interesting family F is to fix another family H of graphs and let F be the set of graphs that do not contain any graph H as some notion of a subgraph\, including (standard) subgraph\, induced subgraph\, and minor. This framework captures numerous basic graph problems\, including Vertex Cover\, Feedback Vertex Set\, and Treewidth Deletion\, and provides an interesting forum where ideas from approximation and parameterized algorithms influence each other. In this talk\, I will give a brief survey on the state of the art on the F-Deletion Problems for the above three notions of subgraphs\, and talk about a recent result on Weighted Bond Deletion.
URL:https://dimag.ibs.re.kr/event/2024-07-30/
LOCATION:Room B332\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
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