Title: From Möbius inversion to renormalisation

Abstract: I will explain how some of the main
abstract features of Hopf-algebraic perturbative
renormalisation, notably Bogoliubov's recursion
and the Atkinson formula, can be understood as
direct generalisation of corresponding features
of classical Möbius inversion, namely the Weisner-
Rota and Hall-Leroux formulae for the Möbius
function.  (No prior knowledge of renormalisation
or Möbius inversion is assumed from the audience.)