10 events found.
Jang Soo Kim (김장수), Longest elements in a semigroup of functions and Slater indices
Room B332 IBS (기초과학연구원)The group \( S_n \) of permutations on \(=\{1,2,\dots,n\} \) is generated by simple transpositions \( s_i = (i,i+1) \). The length \( \ell(\pi) \) of a permutation \( \pi \) is defined to be the minimum number of generators whose product is \( \pi \). It is well-known that the longest element in \( …
IBS-DIMAG Winter School on Graph Minors, Week 2
Room B109 IBS (기초과학연구원)Jungho Ahn (안정호), A coarse Erdős-Pósa theorem for constrained cycles
Room B332 IBS (기초과학연구원)An induced packing of cycles in a graph is a set of vertex-disjoint cycles such that the graph has no edge between distinct cycles of the set. The classic Erdős-Pósa theorem shows that for every positive integer $k$, every graph contains $k$ vertex-disjoint cycles or a set of $O(k\log k)$ vertices which intersects every cycle of $G$. …
IBS-DIMAG Winter School on Graph Minors, Week 3
Room B109 IBS (기초과학연구원)O-joung Kwon (권오정), Erdős-Pósa property of A-paths in unoriented group-labelled graphs
Room B332 IBS (기초과학연구원)A family $\mathcal{F}$ of graphs is said to satisfy the Erdős-Pósa property if there exists a function $f$ such that for every positive integer $k$, every graph $G$ contains either $k$ (vertex-)disjoint subgraphs in $\mathcal{F}$ or a set of at most $f(k)$ vertices intersecting every subgraph of $G$ in $\mathcal{F}$. We characterize the obstructions to …