Tree Process Calculus

We extend Robin Milner's sequential process calculus to tree process calculus in a way similar to that tree automata extend word automata. By this way, we establish a sound and complete inference system which describes the equivalence via bisimulation over tree processes. As a corollary, we obtain a new equivalence relation between tree automata, which is strictly finer than the classical equivalence over tree automata, and is strictly coarser than the equivalence relation via bisimulation defined in [Abdulla P.-A., L. Kaati, and J, Högberg, Bisimulation Minimization of Tree Automata, CIAA (2006), 171–185.].