Jane Tan, Semi-strong colourings of hypergraphs
A vertex colouring of a hypergraph is $c$-strong if every edge $e$ sees at least $\min\{c, |e|\}$ distinct colours. Let $\chi(t,c)$ denote the least number of colours needed so that …
10 events found.
Discrete Math Seminar
Events
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Room B332 IBS (기초과학연구원)
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Maria Chudnovsky, Anticomplete subgraphs of large treewidth
Room B332 IBS (기초과학연구원)We will discuss recent progress on the topic of induced subgraphs and tree-decompositions. In particular this talk with focus on the proof of a conjecture of Hajebi that asserts that …
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Semin Yoo (유세민), Paley-like quasi-random graphs arising from polynomials
Room B332 IBS (기초과학연구원)We provide new constructions of families of quasi-random graphs that behave like Paley graphs but are neither Cayley graphs nor Cayley sum graphs. These graphs give a unified perspective of …
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Wonwoo Kang (강원우), Skein relations for punctured surfaces
Room B332 IBS (기초과학연구원)Since the introduction of cluster algebras by Fomin and Zelevinsky in 2002, there has been significant interest in cluster algebras of surface type. These algebras are particularly noteworthy due to …
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Kisun Lee (이기선), Symmetric Tropical Rank 2 Matrices
Room B332 IBS (기초과학연구원)Tropical geometry replaces usual addition and multiplication with tropical addition (the min) and tropical multiplication (the sum), which offers a polyhedral interpretation of algebraic variety. This talk aims to pitch …
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Hyunwoo Lee (이현우), Random matchings in linear hypergraphs
Room B332 IBS (기초과학연구원)For a given hypergraph $H$ and a vertex $v\in V(H)$, consider a random matching $M$ chosen uniformly from the set of all matchings in $H.$ In $1995,$ Kahn conjectured that …
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Euiwoong Lee (이의웅), Parameterized Approximability of F-Deletion Problems
Room B332 IBS (기초과학연구원)For a family F of graphs, the F-Deletion Problem asks to remove the minimum number of vertices from a given graph G to ensure that G belongs to F. One …
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Daniel Král’, Matroid depth and width parameters
Room B332 IBS (기초과학연구원)Depth and width parameters of graphs, e.g., tree-width, path-width and tree-depth, play a crucial role in algorithmic and structural graph theory. These notions are of fundamental importance in the theory …
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Peter Nelson, Formalizing matroid theory in a proof assistant
Room B332 IBS (기초과학연구원)For the past few years, I've been working on formalizing proofs in matroid theory using the Lean proof assistant. This has led me to many interesting and unexpected places. I'll …
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Dillon Mayhew, Monadic second-order definability for gain-graphic matroids
Room B332 IBS (기초과학연구원)Every (finite) matroid consists of a (finite) set called the ground set, and a collection of distinguished subsets called the independent sets. A classic example arises when the ground set …