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X-ORIGINAL-URL:https://dimag.ibs.re.kr
X-WR-CALDESC:Events for Discrete Mathematics Group
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BEGIN:VTIMEZONE
TZID:Asia/Seoul
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TZOFFSETFROM:+0900
TZOFFSETTO:+0900
TZNAME:KST
DTSTART:20220101T000000
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BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230704T163000
DTEND;TZID=Asia/Seoul:20230704T173000
DTSTAMP:20260419T022239
CREATED:20230627T045021Z
LAST-MODIFIED:20240705T162129Z
UID:7316-1688488200-1688491800@dimag.ibs.re.kr
SUMMARY:Tuan Tran\, Complexity of null dynamical systems
DESCRIPTION:A theoretical dynamical system is a pair (X\,T) where X is a compact metric space and T is a self homeomorphism of X. The topological entropy of a theoretical dynamical system (X\,T)\, first introduced in 1965 by Adler\, Konheim and McAndrew\, is a nonnegative real number that measures the complexity of the system. Systems with positive entropy are random in certain sense\, and systems with zero entropy are said to be deterministic. To distinguish between deterministic systems\, Huang and Ye (2009) introduced the concept of maximal pattern entropy of a theoretical dynamical system. At the heart of their argument is a Sauer-Shelah-type lemma. We will discuss this lemma and its surprising connection to a recent breakthrough in communication complexity. \nJoint work with Guorong Gao\, Jie Ma\, and Mingyuan Rong.
URL:https://dimag.ibs.re.kr/event/2023-07-04/
LOCATION:Room B109\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
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BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230710T163000
DTEND;TZID=Asia/Seoul:20230710T173000
DTSTAMP:20260419T022239
CREATED:20230410T004309Z
LAST-MODIFIED:20240707T073602Z
UID:6987-1689006600-1689010200@dimag.ibs.re.kr
SUMMARY:Xuding Zhu (朱緒鼎)\, List version of 1-2-3 conjecture
DESCRIPTION:The well-known 1-2-3 Conjecture by Karoński\, Łuczak and Thomason states that the edges of any connected graph with at least three vertices can be assigned weights 1\, 2 or 3 so that for each edge $uv$ the sums of the weights at $u$ and at $v$ are distinct. The list version of the 1-2-3 Conjecture by Bartnicki\, Grytczuk and Niwczyk states that the same holds if each edge $e$ has the choice of weights not necessarily from $\{1\,2\,3\}$\, but from any set $\{x(e)\,y(e)\,z(e)\}$ of three real numbers. The goal of this talk is to survey developments on the 1-2-3 Conjecture\, especially on the list version of the 1-2-3 Conjecture.
URL:https://dimag.ibs.re.kr/event/2023-07-10/
LOCATION:Room B109\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
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BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230713T094000
DTEND;TZID=Asia/Seoul:20230713T105000
DTSTAMP:20260419T022239
CREATED:20230711T000049Z
LAST-MODIFIED:20240705T162121Z
UID:7377-1689241200-1689245400@dimag.ibs.re.kr
SUMMARY:Open Symposium at the Discrete Mathematics Group
DESCRIPTION:Program\n\n9:40-10:05: Sang-il OUM\, Obstructions for dense analogs of tree-depth\n10:05-10:20: Kevin HENDREY\, Structural and extremal results for twin-width\n10:20-10:35: Rutger CAMPBELL\, Down-sets in combinatorial posets\n10:35-10:50: Linda COOK\, Reuniting 𝜒-boundedness with polynomial 𝜒-boundedness
URL:https://dimag.ibs.re.kr/event/2023-07-11/
LOCATION:Room B109\, IBS (기초과학연구원)
CATEGORIES:Workshops and Conferences
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230718T163000
DTEND;TZID=Asia/Seoul:20230718T173000
DTSTAMP:20260419T022239
CREATED:20230601T142456Z
LAST-MODIFIED:20240705T163017Z
UID:7226-1689697800-1689701400@dimag.ibs.re.kr
SUMMARY:Andrzej Grzesik\, Rainbow Turán problems
DESCRIPTION:In a rainbow variant of the Turán problem\, we consider $k$ graphs on the same set of vertices and want to determine the smallest possible number of edges in each graph\, which guarantees the existence of a copy of a given graph $F$ containing at most one edge from each graph. In other words\, we treat each of the $k$ graphs as a graph in one of the $k$ colors and consider how many edges in each color force a rainbow copy of a given graph $F$. In the talk\, we will describe known results on the topic\, as well as present recent developments\, obtained jointly with Sebastian Babiński and Magdalen Prorok\, solving the rainbow Turán problem for a path on 4 vertices and a directed triangle with any number of colors.
URL:https://dimag.ibs.re.kr/event/2023-07-18/
LOCATION:Room S221\, IBS (기초과학연구원) Science Culture Center
CATEGORIES:Discrete Math Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Asia/Seoul:20230725T163000
DTEND;TZID=Asia/Seoul:20230725T173000
DTSTAMP:20260419T022239
CREATED:20230615T122924Z
LAST-MODIFIED:20240707T073405Z
UID:7282-1690302600-1690306200@dimag.ibs.re.kr
SUMMARY:Dong Yeap Kang (강동엽)\, Hamilton cycles and optimal matchings in a random subgraph of uniform Dirac hypergraphs
DESCRIPTION:A loose cycle is a cyclic ordering of edges such that every two consecutive edges share exactly one vertex. A cycle is Hamilton if it spans all vertices. A codegree of a $k$-uniform hypergraph is the minimum nonnegative integer $t$ such that every subset of vertices of size $k-1$ is contained in $t$ distinct edges. \nWe prove “robust” versions of Dirac-type theorems for Hamilton cycles and optimal matchings. \nLet $\mathcal{H}$ be a $k$-uniform hypergraph on $n$ vertices with $n \in (k-1)\mathbb{N}$ and codegree at least $n/(2k-2)$\, and let $\mathcal{H}_p$ be a spanning subgraph of $\mathcal{H}$ such that each edge of $\mathcal{H}$ is included in $\mathcal{H}_p$ with probability $p$ independently at random. We prove that a.a.s. $\mathcal{H}_p$ contains a loose Hamilton cycle if $p = \Omega(n^{-k+1} \log n)$\, which is asymptotically best possible. We also present similar results for Hamilton $\ell$-cycles for $\ell \geq 2$. \nFurthermore\, we prove that if $\mathcal{H}$ is a $k$-uniform hypergraph on $n$ vertices with $n \notin k \mathbb{N}$ and codegree at least $\lfloor n/k \rfloor$\, then a.a.s. $\mathcal{H}_p$ contains a matching of size $\lfloor n/k \rfloor$ if $p = \Omega(n^{-k+1} \log n)$. This is also asymptotically best possible. \nThis is joint work with Michael Anastos\, Debsoumya Chakraborti\, Abhishek Methuku\, and Vincent Pfenninger.
URL:https://dimag.ibs.re.kr/event/2023-07-25/
LOCATION:Room B332\, IBS (기초과학연구원)
CATEGORIES:Discrete Math Seminar
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