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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Seminars and Colloquiums
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.
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 …
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 …
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 $t$ …
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 …
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 …
Jungho Ahn (안정호), Well-partitioned chordal graphs with the obstruction set and applications
Room B232 IBS (기초과학연구원)We introduce a new subclass of chordal graphs that generalizes split graphs, which we call well-partitioned chordal graphs. Split graphs are graphs that admit a partition of the vertex set …
Raul Lopes, Adapting the Directed Grid Theorem into an FPT Algorithm
Zoom ID: 869 4632 6610 (ibsdimag)The Grid Theorem of Robertson and Seymour is one of the most important tools in the field of structural graph theory, finding numerous applications in the design of algorithms for …
Hong Liu, Sublinear expander and embeddings sparse graphs
ZoomA notion of sublinear expander has played a central role in the resolutions of a couple of long-standing conjectures in embedding problems in graph theory, including e.g. the odd cycle …