Distortion and tree-width of knots after Pardon, Guth-Gromov and work of the speaker with some colleagues.

Orateur: Arnaud DE MESMAY
Localisation: Université Gustave Eiffel, France
Type: Groupe de travail théorie du min-max
Site: UGE , 4B 107
Date de début: 28/01/2020 - 16:00
Date de fin: 23/01/2020 - 08:41

Given a number $m$ there are knots so that no matter the embedding of the knot there exists a pair of points $x,y$ such that $d_K(x,y)/|x-y|>m$. Here $|x-y$| is the distance for a bird and $d_K(x,y)$ is the distance for an ant walking on the knot. In the proof the tree-width will be a key invariant of independent interest.