Cosmin Pohoata, Convex polytopes from fewer points
Finding the smallest integer $N=ES_d(n)$ such that in every configuration of $N$ points in $\mathbb{R}^d$ in general position, there exist $n$ points in convex position is one of the most …
10 events found.
Virtual Discrete Math Colloquium
Events
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Zoom ID: 224 221 2686 (ibsecopro)
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Maya Sankar, Homotopy and the Homomorphism Threshold of Odd Cycles
Zoom ID: 224 221 2686 (ibsecopro)Fix $r \ge 2$ and consider a family F of $C_{2r+1}$-free graphs, each having minimum degree linear in its number of vertices. Such a family is known to have bounded …
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Pedro Montealegre, A Meta-Theorem for Distributed Certification
Zoom ID: 869 4632 6610 (ibsdimag)Distributed certification, whether it be proof-labeling schemes, locally checkable proofs, etc., deals with the issue of certifying the legality of a distributed system with respect to a given boolean predicate. A certificate …
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Jan Hladký, Invitation to graphons
Zoom ID: 224 221 2686 (ibsecopro)The first course in graph theory usually covers concepts such as matchings, independent sets, colourings, and forbidden subgraphs. Around 2004, Borgs, Chayes, Lovász, Sós, Szegedy, and Vestergombi introduced a very …
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Benjamin Bergougnoux, Tight Lower Bounds for Problems Parameterized by Rank-width
Zoom ID: 869 4632 6610 (ibsdimag)We show that there is no $2^{o(k^2)} n^{O(1)}$ time algorithm for Independent Set on $n$-vertex graphs with rank-width $k$, unless the Exponential Time Hypothesis (ETH) fails. Our lower bound matches …
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Robert Hickingbotham, Treewidth, Circle Graphs and Circular Drawings
Zoom ID: 869 4632 6610 (ibsdimag)A circle graph is an intersection graph of a set of chords of a circle. In this talk, I will describe the unavoidable induced subgraphs of circle graphs with large …
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Daniel Altman, On an arithmetic Sidorenko conjecture, and a question of Alon
Zoom ID: 224 221 2686 (ibsecopro)Let $G=\mathbb{F}_p^n$. Which systems of linear equations $\Psi$ have the property that amongst all subsets of $G$ of fixed density, random subsets minimise the number of solutions to $\Psi$? This …
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Marcelo Sales, On Pisier type problems
Zoom ID: 224 221 2686 (ibsecopro)A subset $A\subseteq \mathbb Z$ of integers is free if for every two distinct subsets $B, B'\subseteq A$ we have \Pisier asked if for every subset $A\subseteq \mathbb Z$ of …
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Paul Seymour, A loglog step towards the Erdős-Hajnal conjecture
Zoom ID: 869 4632 6610 (ibsdimag)In 1977, Erdős and Hajnal made the conjecture that, for every graph $H$, there exists $c>0$ such that every $H$-free graph $G$ has a clique or stable set of size …
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Qizhong Lin, Two classical Ramsey-Turán numbers involving triangles
Zoom ID: 224 221 2686 (ibsecopro)In 1993, Erdős, Hajnal, Simonovits, Sós and Szemerédi proposed to determine the value of Ramsey-Turán density $\rho(3,q)$ for $q\ge3$. Erdős et al. (1993) and Kim, Kim and Liu (2019) proposed …