Séminaire QUID

Quid seminar : Combinatorics of walks in the quadrant

by Pierre Bonnet (LaBRI - Université de Bordeaux)

Room Picard (1R2-129)

Room Picard (1R2-129)


Consider the following problem: for S a subset of Z^2, we want 
to count the plane lattice walks with steps in S, that start from (0,0) 
and always remain in the first quadrant. This enumerative combinatorics 
problem is extremely hard, and still an active research topic. In this 
talk, I will first give a gentle introduction to the use of generating 
functions in enumerative combinatorics. Afterwards, I will treat one 
particular case of this problem, which will shed some light on the 
formidable richness of the tools used in its study.