Stijn Cambie, Recent progress on the Union-closed conjecture and related
We give a summary on the work of the last months related to Frankl's Union-Closed conjecture and its offsprings. The initial conjecture is stated as a theorem in extremal set …
10 events found.
Discrete Math Seminar
Events
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Room B332 IBS (기초과학연구원)
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Younjin Kim (김연진), Problems on Extremal Combinatorics
Room B332 IBS (기초과학연구원)Extremal Combinatorics studies the maximum or minimum size of finite objects (numbers, sets, graphs) satisfying certain properties. In this talk, I introduce the conjectures I solved on Extremal Combinatorics, and …
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Tianchi Yang, On the maximum number of edges in k-critical graphs
Room B332 IBS (기초과학연구원)In this talk, we will discuss the problem of determining the maximum number of edges in an n-vertex k-critical graph. A graph is considered k-critical if its chromatic number is …
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István Tomon, Configurations of boxes
Room B332 IBS (기초과학연구원)Configurations of axis-parallel boxes in $\mathbb{R}^d$ are extensively studied in combinatorial geometry. Despite their perceived simplicity, there are many problems involving their structure that are not well understood. I will …
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James Davies, Two structural results for pivot-minors
Room B332 IBS (기초과학연구원)Pivot-minors can be thought of as a dense analogue of graph minors. We shall discuss pivot-minors and two recent results for proper pivot-minor-closed classes of graphs. In particular, that for …
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Hyunwoo Lee (이현우), On perfect subdivision tilings
Room B332 IBS (기초과학연구원)For a given graph $H$, we say that a graph $G$ has a perfect $H$-subdivision tiling if $G$ contains a collection of vertex-disjoint subdivisions of $H$ covering all vertices of …
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Rob Morris, An exponential improvement for diagonal Ramsey
Room B332 IBS (기초과학연구원)The Ramsey number $R(k)$ is the minimum n such that every red-blue colouring of the edges of the complete graph on n vertices contains a monochromatic copy of $K_k$. It …
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Jozef Skokan, Separating the edges of a graph by a linear number of paths
Room B332 IBS (기초과학연구원)Recently, Letzter proved that any graph of order n contains a collection P of $O(n \log^*n)$ paths with the following property: for all distinct edges e and f there exists …
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Oliver Janzer, Small subgraphs with large average degree
Room B332 IBS (기초과학연구원)We study the fundamental problem of finding small dense subgraphs in a given graph. For a real number $s>2$, we prove that every graph on $n$ vertices with average degree …
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Suyun Jiang (江素云), How connectivity affects the extremal number of trees
Room B332 IBS (기초과학연구원)The Erdős-Sós conjecture states that the maximum number of edges in an $n$-vertex graph without a given $k$-vertex tree is at most $\frac {n(k-2)}{2}$. Despite significant interest, the conjecture remains …