Kevin Hendrey, Extremal functions for sparse minors
Room B232 IBS (기초과학연구원)The extremal function $c(H)$ of a graph $H$ is the supremum of densities of graphs not containing $H$ as a minor, where the density of a graph is the ratio …
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Péter Pál Pach, The Alon-Jaeger-Tarsi conjecture via group ring identities
Zoom ID: 869 4632 6610 (ibsdimag)The Alon-Jaeger-Tarsi conjecture states that for any finite field $\mathbb{F}$ of size at least 4 and any nonsingular matrix $M$ over $\mathbb{F}$ there exists a vector $x$ such that neither …
Eunjin Oh (오은진), Feedback Vertex Set on Geometric Intersection Graphs
Room B232 IBS (기초과학연구원)I am going to present an algorithm for computing a feedback vertex set of a unit disk graph of size k, if it exists, which runs in time $2^{O(\sqrt{k})}(n + …
Paul Seymour, Polynomial bounds for chromatic number
Zoom ID: 869 4632 6610 (ibsdimag)The Gyárfás-Sumner conjecture says that for every forest $H$, there is a function $f$ such that the chromatic number $\chi(G)$ is at most $f(\omega(G))$ for every $H$-free graph $G$ ("$H$-free" means with …
Joonkyung Lee (이준경), Majority dynamics on sparse random graphs
Room B232 IBS (기초과학연구원)Majority dynamics on a graph $G$ is a deterministic process such that every vertex updates its $\pm 1$-assignment according to the majority assignment on its neighbor simultaneously at each step. …
Young Researchers in Extremal and Probabilistic Combinatorics
Zoom ID: 554 788 7710 (507464)The aim of the Young Researchers in Extremal and Probabilistic Combinatorics is to bring together early career researchers working on these topics. The workshop will consist of several 25 minute …
Donggyu Kim (김동규), 𝝘-graphic delta-matroids and their applications
Room B232 IBS (기초과학연구원)Bouchet (1987) defined delta-matroids by relaxing the base exchange axiom of matroids. Oum (2009) introduced a graphic delta-matroid from a pair of a graph and its vertex subset. We define …
Ben Lund, Maximal 3-wise intersecting families
Room B232 IBS (기초과학연구원)A family $\mathcal F$ of subsets of {1,2,…,n} is called maximal k-wise intersecting if every collection of at most k members from $\mathcal F$ has a common element, and moreover, …
Martin Milanič, Tree Decompositions with Bounded Independence Number
Zoom ID: 869 4632 6610 (ibsdimag)The independence number of a tree decomposition $\mathcal{T}$ of a graph is the smallest integer $k$ such that each bag of $\mathcal{T}$ induces a subgraph with independence number at most …
Jaehoon Kim (김재훈), 2-complexes with unique embeddings in 3-space
Room B232 IBS (기초과학연구원)A well-known theorem of Whitney states that a 3-connected planar graph admits an essentially unique embedding into the 2-sphere. We prove a 3-dimensional analogue: a simply-connected 2-complex every link graph …