A Finite Equational Base for CCS with Left Merge and Communication Merge
  Using the left merge and communication merge from ACP, we present an equational base (i.e., a ground-complete and $\omega$-complete set of valid equations) for the fragment of CCS without recursion, restriction and relabelling. Our equational base is finite if the set of actions is finite. 
Luca Aceto, Wan Fokkink, Anna Ingolfsdottir, and Bas Luttik