| Equipe(s) : | tga, |
| Responsables : | Catherine Gille et Najib Idrissi |
| Email des responsables : | |
| Salle : | 1016 |
| Adresse : | Sophie Germain |
| Description | Un plan d’accès est disponible ici. Pour vous inscrire à la liste de diffusion du séminaire, veuillez vous rendre à cette adresse. |
| Orateur(s) | Livio LIECHTI - IMJ-PRG, |
| Titre | Forbidden minor characterisations and the topological 4-genus |
| Date | 13/03/2018 |
| Horaire | 11:00 à 12:00 |
| |
| Résume | Famously, a finite graph is planar exactly if it does not admit two specific graphs as minors. In fact, a characterisation by finitely many forbidden minors exists for any property which passes to minors with respect to a well-quasi-order. In this context, we discuss a minor relation for Seifert surfaces embedded in three-space, defined by isotopy into an incompressible subsurface, and the property to have an equality between the ordinary Seifert genus and the topological 4-genus of the boundary knot. In particular, we characterise this equality in the case of positive braid knots.
|
| Salle | 1016 |
| Adresse | Sophie Germain |