A matching theoretic approach to structural digraph theory

Speaker: Sebastian Wiederrecht (TU Berlin)

Abstract: The theory of butterfly minors in digraphs which is closely linked to the notion of directed treewidth has become an active field of research in the past years. Many great advancements have been made such as a directed version of the famous Grid Theorem and several other generalisations of great results from the Graph Minors Series of Robterson and Seymour. However, many of these results appear flawed when first encountered: The Erdos-Posa property of butterfly minors does not appear to be linked to a topological property, and the directed version of the Flat Wall is not actually flat. In this talk we identify two possible reasons for these flaws and show how recent advancements in the area of structural matching theory can be used, by rethinking the way we handle butterfly minors and unavoidable infinite anti-chains of them, to achieve much nicer results.

Date and time: 21/01/2021 at 14:30 (Paris time)

Link to the talk: https://bbb-temp.grenet.fr/b/lou-9x7-69p