Invited Talk: Marcello Bonsangue

The algebra of regular expressions for polynomial T-coalgebras

For polynomial set functors T, we introduce a language of 'regular expressions' for describing T-coalgebras. We show that, up to bisimulation, states of a finite coalgebra are in one-to-one correspondence with regular expressions. Further, we present a finitary axiomatization of the algebra of regular expressions in terms of equations and disequations.