Seunghun Lee (이승훈), Inscribable order types
Room B332 IBS (기초과학연구원)We call an order type inscribable if it is realized by a point configuration where all extreme points are all on a circle. In this talk, we investigate inscribability of …
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Seminars and Colloquiums
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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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Eun Jung Kim (김은정), Directed flow-augmentation
Room B332 IBS (기초과학연구원)We show a flow-augmentation algorithm in directed graphs: There exists a polynomial-time algorithm that, given a directed graph G, two integers $s,t\in V(G)$, and an integer $k$, adds (randomly) to …
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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 …
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Noleen Köhler, Testing first-order definable properties on bounded degree graphs
Room B332 IBS (기초과학연구원)Property testers are probabilistic algorithms aiming to solve a decision problem efficiently in the context of big-data. A property tester for a property P has to decide (with high probability …
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Raul Lopes, Temporal Menger and related problems
Room B332 IBS (기초과학연구원)A temporal graph is a graph whose edges are available only at specific times. In this scenario, the only valid walks are the ones traversing adjacent edges respecting their availability, …
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Brett Leroux, Expansion of random 0/1 polytopes
Zoom ID: 870 0312 9412 (ibsecopro) [CLOSED]A conjecture of Milena Mihail and Umesh Vazirani states that the edge expansion of the graph of every $0/1$ polytope is at least one. Any lower bound on the edge expansion gives …
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Jun Gao, Number of (k-1)-cliques in k-critical graph
Room B332 IBS (기초과학연구원)We prove that for $n>k\geq 3$, if $G$ is an $n$-vertex graph with chromatic number $k$ but any its proper subgraph has smaller chromatic number, then $G$ contains at most …
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Raphael Steiner, Congruence-constrained subdivisions in digraphs
Zoom ID: 869 4632 6610 (ibsdimag)I will present the short proof from that for every digraph F and every assignment of pairs of integers $(r_e,q_e)_{e\in A(F)}$ to its arcs, there exists an integer $N$ such …
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Bjarne Schülke, A local version of Katona’s intersection theorem
Room B332 IBS (기초과학연구원)Katona's intersection theorem states that every intersecting family $\mathcal F\subseteq^{(k)}$ satisfies $\vert\partial\mathcal F\vert\geq\vert\mathcal F\vert$, where $\partial\mathcal F=\{F\setminus x:x\in F\in\mathcal F\}$ is the shadow of $\mathcal F$. Frankl conjectured that for …