Branching Bisimilarity with Explicit Divergence
  We consider the relational characterisation of branching bisimilarity with explicit divergence. We prove that it is an equivalence and that it coincides with the original definition of branching bisimilarity with explicit divergence in terms of coloured traces. We also establish a correspondence with several variants of an action-based modal logic with until- and divergence modalities. 
Rob van Glabbeek, Bas Luttik and Nikola Trcka