A logic approach to guarded and unguarded recursion

The aim of this paper is to study the aspect of recursion in the framework of the temporal semantics of action prefix (CCS-like) languages. The use of minimal and maximal fixed point temporal semantics, defined on a specific temporal logic, is proposed as a suitable tool for a deep analysis of possible semantics for guarded and unguarded recursion. This paper shows the results of this study on possible forms of guarded and unguarded recursion for a simple action language: minimal and maximal fixed point temporal semantics for guarded recursive processes differ only for infinite behaviours, while for unguarded recursive processes they differ completely.