Hong Liu (刘鸿), Nested cycles with no geometric crossing
In 1975, Erdős asked the following question: what is the smallest function $f(n)$ for which all graphs with $n$ vertices and $f(n)$ edges contain two edge-disjoint cycles $C_1$ and $C_2$, …
10 events found.
Seminars and Colloquiums
Events
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Room B232 IBS (기초과학연구원)
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Édouard Bonnet, Twin-width and ordered binary structures
Zoom ID: 869 4632 6610 (ibsdimag)The twin-width of a graph G can be defined as the least integer d such that there is a sequence of length |V(G)| of (strictly) coarser and coarser partitions of …
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Casey Tompkins, 3-uniform hypergraphs avoiding a cycle of length four
Room B232 IBS (기초과학연구원)We show that that the maximum number of of edges in a $3$-uniform hypergraph without a Berge-cycle of length four is at most $(1+o(1)) \frac{n^{3/2}}{\sqrt{10}}$. This improves earlier estimates by …
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Sophie Spirkl, Pure pairs in ordered graphs
Zoom ID: 869 4632 6610 (ibsdimag)A pure pair in a graph G is a pair of subsets A, B of the vertex set of G such that in G, either all of the edges or …
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Rutger Campbell, Matroid orientability and representability
Room B232 IBS (기초과학연구원)In this talk we will have a brief introduction to oriented matroids and their relation to real-representability.
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Michał Pilipczuk, Structural properties of powers of sparse graphs
Zoom ID: 869 4632 6610 (ibsdimag)For a graph G and an integer d, the dth power of G is the graph $G^d$ on the same vertex set as G where two vertices are considered adjacent …
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William Overman, Some Ordered Ramsey Numbers of Graphs on Four Vertices
Room B232 IBS (기초과학연구원)Ordered Ramsey numbers were introduced in 2014 by Conlon, Fox, Lee, and Sudakov. Their results included upper bounds for general graphs and lower bounds showing separation from classical Ramsey numbers. We …
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István Tomon, Ramsey properties of semilinear graphs
Zoom ID: 869 4632 6610 (ibsdimag)A graph $G$ is semilinear of bounded complexity if the vertices of $G$ are elements of $\mathbb{R}^{d}$, and the edges of $G$ are defined by the sign patterns of $t$ …
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Sang-il Oum (엄상일), What is an isotropic system?
Room B232 IBS (기초과학연구원)Bouchet introduced isotropic systems in 1983 unifying some combinatorial features of binary matroids and 4-regular graphs. The concept of isotropic system is a useful tool to study vertex-minors of graphs …
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Reinhard Diestel, Tangles of set separations: a novel clustering method and type recognition in machine learning
Zoom ID: 869 4632 6610 (ibsdimag)Traditional clustering identifies groups of objects that share certain qualities. Tangles do the converse: they identify groups of qualities that typically occur together. They can thereby discover, relate, and structure …