This paper deals with bisimulation quantifiers logic BQL, that is, the extension of propositional
dynamic logic PDL with the so-called “bisimulation quantifiers”. This logic is expressively equivalent
to the -calculus (an extension of modal logic with extremal fixpoints), albeit its formulas are easier
to understand. In this work we provide a complete axiomatization of BQL, based on certain normal
form results for the mu-calculus obtained by Janin and Walukiewicz.
