2021-05-31 10:00 — 11:00 Zoom Michael Vyalyi (HSE University , Russia) Re-pairing brackets The re-pairing problem is a recently discovered combinatorial problem concerning Dyck words. We have first identified the re-pairing problem when studying an open question in automata theory,…

2021-05-24 10:00 — 11:00 Zoom Matjaž Krnc (UP FAMNIT, Slovenia) Shifting any path to an avoidable one A vertex  in a graph  is avoidable if every induced path on three vertices with middle vertex  is contained in an induced cycle. Dirac’s classical result…

2021-05-17 10:00 — 11:00 Zoom Blas Fernández (UP IAM, Slovenia) On 2-Y-homogeneous and almost 2-Y-homogeneos distance-biregular graphs Let G denote a distance-biregular graph with bipartite parts Y and Y’. Let D denote the eccentricity of vertices in Y. Given a…

2021-05-10 10:00 — 11:00 Zoom Slobodan Filipovski (UP FAMNIT) On the clique number and Mantel/Turan theorems Let G=(V,E) be a finite undirected graph with vertex set V(G) of order |V(G)|=n and edge set E(G) of size |E(G)|=m. Let d_{1}\geq d_{2}\geq…\geq d_{n} be…

2021-05-03 10:00 — 11:00 Zoom Tomaž Pisanski (UP FAMNIT and UL FMF). Embeddings of Action Graphs In the literature, one can find at least three different genus parameters associated with a finite group: genus, symmetric genus, and strong symmetric genus. While…