Divide and Congruence II: Delay and Weak Bisimilarity

Abstract

Earlier we presented a method to decompose modal formulas for processes with the internal action τ; congruence formats for branching and η-bisimilarity were derived on the basis of this decomposition method. The idea is that a congruence format for a semantics must ensure that formulas in the modal characterisation of this semantics are always decomposed into formulas in this modal characterisation. Here the decomposition method is enhanced to deal with modal characterisations that contain a modality 〈ϵ〉〈α〉φ, to derive congruence formats for delay and weak bisimilarity.