# Lecture by Eric Fusy (École Polytechnique Paris): Bijections between families of walks using oriented planar maps

When counting walks (with a given step-set), an equi-enumeration phenomenom is often observed between a stronger constraint on the domain and a stronger constraint on the position of the endpoint (a classical one-dimensional example is the fact that positive walks of length 2*n* are in bijection with walks of length 2*n* ending at 0, both being counted by the central binomial coefficient). I will show examples of such relations for 2*d* walks where the equi-enumeration can be bijectively explained using planar maps endowed with certain orientations (Schnyder woods, bipolar orientations).

### Time & Location

Jan 13, 2020 | 02:15 PM

Technische Universität Berlin

Institut für Mathematik

Straße des 17. Juni 136

10623 Berlin

Room MA 041 (Ground Floor)