Olivier Bouillot (Université Paris-Est Marne-la-Vallée)
Mould calculus is a powerful combinatorial tool which has been developed in the
late 80's by J. Ecalle. It often provides some explicit formulae when there are
no other available computational methods.
In this conference, we will review the primary symmetries of moulds (ie
functions with a variable number of variables) and their Hopf algebraic
interpretation. Then, we will develop the Hopf algebraic interpretation of the
secondary mould symmetries.