Boram Park (박보람), Odd coloring of sparse graphs
Room B232 IBS (기초과학연구원)We introduce an odd coloring of a graph, which was introduced very recently, motivated by parity type colorings of graphs. A proper vertex coloring of graph
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Seminars and Colloquiums
Michael Savery, Induced subgraphs of induced subgraphs of large chromatic number
Zoom ID: 869 4632 6610 (ibsdimag)We prove that for every graph F with at least one edge there are graphs H of arbitrarily large chromatic number and the same clique number as F such that every F-free induced subgraph of H has chromatic number at most c=c(F). (Here a graph is F-free if it does not contain an induced copy …
Cheolwon Heo (허철원), The complexity of the matroid-homomorphism problems
Room B332 IBS (기초과학연구원)In this talk, we introduce homomorphisms between binary matroids that generalize graph homomorphisms. For a binary matroid
Kyeongsik Nam (남경식), Large deviations for subgraph counts in random graphs
Room B332 IBS (기초과학연구원)The upper tail problem for subgraph counts in the Erdos-Renyi graph, introduced by Janson-Ruciński, has attracted a lot of attention. There is a class of Gibbs measures associated with subgraph counts, called exponential random graph model (ERGM). Despite its importance, lots of fundamental questions have remained unanswered owing to the lack of exact solvability. In …
Andreas Holmsen, A colorful version of the Goodman-Pollack-Wenger transversal theorem
Room B332 IBS (기초과학연구원)Hadwiger's transversal theorem gives necessary and sufficient conditions for the existence of a line transversal to a family of pairwise disjoint convex sets in the plane. These conditions were subsequently generalized to hyperplane transversals in
Jan Kurkofka, Canonical Graph Decompositions via Coverings
Zoom ID: 869 4632 6610 (ibsdimag)We present a canonical way to decompose finite graphs into highly connected local parts. The decomposition depends only on an integer parameter whose choice sets the intended degree of locality. The global structure of the graph, as determined by the relative position of these parts, is described by a coarser model. This is a simpler …
Gil Kalai, The Cascade Conjecture and other Helly-type Problems
Zoom ID: 868 7549 9085For a set
Stijn Cambie, The precise diameter of reconfiguration graphs
Room B332 IBS (기초과학연구원)Reconfiguration is about changing instances in small steps. For example, one can perform certain moves on a Rubik's cube, each of them changing its configuration a bit. In this case, in at most 20 steps, one can end up with the preferred result. One could construct a graph with as nodes the possible configurations of …
Sebastian Siebertz, Transducing paths in graph classes with unbounded shrubdepth
Zoom ID: 869 4632 6610 (ibsdimag)Transductions are a general formalism for expressing transformations of graphs (and more generally, of relational structures) in logic. We prove that a graph class C can be FO-transduced from a class of bounded-height trees (that is, has bounded shrubdepth) if, and only if, from C one cannot FO-transduce the class of all paths. This establishes …
Hongseok Yang (양홍석), Learning Symmetric Rules with SATNet
Room B332 IBS (기초과학연구원)SATNet is a differentiable constraint solver with a custom backpropagation algorithm, which can be used as a layer in a deep-learning system. It is a promising proposal for bridging deep learning and logical reasoning. In fact, SATNet has been successfully applied to learn, among others, the rules of a complex logical puzzle, such as Sudoku, …