Michael Savery, Induced subgraphs of induced subgraphs of large chromatic number
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 …
10 events found.
Virtual Discrete Math Colloquium
Events
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Zoom ID: 869 4632 6610 (ibsdimag)
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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. …
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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 …
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Jeck Lim, Sums of linear transformations
Zoom ID: 870 0312 9412 (ibsecopro) [CLOSED]We show that if $L_1$ and $L_2$ are linear transformations from $\mathbb{Z}^d$ to $\mathbb{Z}^d$ satisfying certain mild conditions, then, for any finite subset $A$ of $\mathbb{Z}^d$, \ This result corrects …
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Chengfei Xie, On the packing densities of superballs in high dimensions
Zoom ID: 870 0312 9412 (ibsecopro) [CLOSED]The sphere packing problem asks for the densest packing of nonoverlapping equal-sized balls in the space. This is an old and difficult problem in discrete geometry. In this talk, we …
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Xizhi Liu, Hypergraph Turán problem: from 1 to ∞
Zoom ID: 870 0312 9412 (ibsecopro) [CLOSED]One interesting difference between (nondegenerate) Graph Turán problem and Hypergraph Turán problem is that the hypergraph families can have at least two very different extremal constructions. In this talk, we …
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Sepehr Hajebi, Holes, hubs and bounded treewidth
Zoom ID: 869 4632 6610 (ibsdimag)A hole in a graph $G$ is an induced cycle of length at least four, and for every hole $H$ in $G$, a vertex $h\in G\setminus H$ is called a …
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Noam Lifshitz, Product free sets in the alternating group
Zoom ID: 870 0312 9412 (ibsecopro) [CLOSED]A subset of a group is said to be product free if it does not contain the product of two elements in it. We consider how large can a product …
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Lars Jaffke, Taming graphs with no large creatures and skinny ladders
Zoom ID: 869 4632 6610 (ibsdimag)We confirm a conjecture of Gartland and Lokshtanov : if for a hereditary graph class $\mathcal{G}$ there exists a constant $k$ such that no member of $\mathcal{G}$ contains a $k$-creature …
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Akash Kumar, Random walks and Forbidden Minors
Zoom ID: 870 0312 9412 (ibsecopro) [CLOSED]Random walks and spectral methods have had a strong influence on modern graph algorithms as evidenced by the extensive literature on the subject. In this talk, I will present how …