BEGIN:VCALENDAR
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PRODID:-//Discrete Mathematics Group - ECPv6.0.1.1//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:20220101T000000
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BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20221011T163000
DTEND;TZID=Asia/Seoul:20221011T173000
DTSTAMP:20221006T221221
CREATED:20220824T132239Z
LAST-MODIFIED:20220824T133846Z
UID:6067-1665505800-1665509400@dimag.ibs.re.kr
SUMMARY:Nika Salia\, Exact results for generalized extremal problems forbidding an even cycle
DESCRIPTION:We determine the maximum number of copies of $K_{s\,s}$ in a $C_{2s+2}$-free $n$-vertex graph for all integers $s \ge 2$ and sufficiently large $n$. Moreover\, for $s\in\{2\,3\}$ and any integer $n$ we obtain the maximum number of cycles of length $2s$ in an $n$-vertex $C_{2s+2}$-free bipartite graph. \nThis is joint work with Ervin Győri (Renyi Institute)\, Zhen He (Tsinghua University)\, Zequn Lv (Tsinghua University)\, Casey Tompkins (Renyi Institute)\, Kitti Varga (Technical University of Budapest BME)\, and Xiutao Zhu (Nanjing University).
URL:https://dimag.ibs.re.kr/event/2022-10-11/
LOCATION:Room B332\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
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BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20221013T161500
DTEND;TZID=Asia/Seoul:20221013T171500
DTSTAMP:20221006T221221
CREATED:20221006T054719Z
LAST-MODIFIED:20221006T054719Z
UID:6264-1665677700-1665681300@dimag.ibs.re.kr
SUMMARY:Xavier Goaoc\, Order types and their symmetries
DESCRIPTION:Order types are a combinatorial classification of finite point sets used in discrete and computational geometry. This talk will give an introduction to these objects and their analogue for the projective plane\, with an emphasis on their symmetry groups. \nThis is joint work with Emo Welzl.
URL:https://dimag.ibs.re.kr/event/2022-10-13/
LOCATION:Room 1501\, Bldg. E6-1\, KAIST
CATEGORIES:Colloquium
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20221018T163000
DTEND;TZID=Asia/Seoul:20221018T173000
DTSTAMP:20221006T221221
CREATED:20220824T133830Z
LAST-MODIFIED:20221005T084155Z
UID:6071-1666110600-1666114200@dimag.ibs.re.kr
SUMMARY:Florent Koechlin\, Uniform random expressions lack expressivity
DESCRIPTION:In computer science\, random expressions are commonly used to analyze algorithms\, either to study their average complexity\, or to generate benchmarks to test them experimentally. In general\, these approaches only consider the expressions as purely syntactic trees\, and completely ignore their semantics — i.e. the mathematical object represented by the expression. \nHowever\, two different expressions can be equivalent (for example “0*(x+y)” and “0” represent the same expression\, the null expression). Can these redundancies question the relevance of the analyses and tests that do not take into account the semantics of the expressions? \nI will present how the uniform distribution over syntactic expression becomes completely degenerate when we start taking into account their semantics\, in a very simple but common case where there is an absorbing element. If time permits it\, I will briefly explain why the BST distribution offers more hope. \nThis is a joint work with Cyril Nicaud and Pablo Rotondo.
URL:https://dimag.ibs.re.kr/event/2022-10-18/
LOCATION:Room B332\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20221129T163000
DTEND;TZID=Asia/Seoul:20221129T173000
DTSTAMP:20221006T221221
CREATED:20220908T152618Z
LAST-MODIFIED:20220908T222634Z
UID:6153-1669739400-1669743000@dimag.ibs.re.kr
SUMMARY:Giannos Stamoulis\, Model-Checking for First-Order Logic with Disjoint Paths Predicates in Proper Minor-Closed Graph Classes
DESCRIPTION:The disjoint paths logic\, FOL+DP\, is an extension of First Order Logic (FOL) with the extra atomic predicate $\mathsf{dp}_k(x_1\,y_1\,\ldots\,x_k\,y_k)\,$ expressing the existence of internally vertex-disjoint paths between $x_i$ and $y_i\,$ for $i\in \{1\,\ldots\, k\}$. This logic can express a wide variety of problems that escape the expressibility potential of FOL. We prove that for every minor-closed graph class\, model-checking for FOL+DP can be done in quadratic time. We also introduce an extension of FOL+DP\, namely the scattered disjoint paths logic\, FOL+SDP\, where we further consider the atomic predicate $\mathsf{s-sdp}_k(x_1\,y_1\,\ldots\,x_k\,y_k)\,$ demanding that the disjoint paths are within distance bigger than some fixed value $s$. Using the same technique we prove that model-checking for FOL+SDP can be done in quadratic time on classes of graphs with bounded Euler genus.\nJoint work with Petr A. Golovach and Dimitrios M. Thilikos.
URL:https://dimag.ibs.re.kr/event/2022-11-29/
LOCATION:Room B332\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
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