 
Summary: Deriving Complete Inference Systems for a Class of GSOS
Languages Generating Regular Behaviours
Luca Aceto \Lambda
School of Cognitive and Computing Studies,
University of Sussex,
Falmer, Brighton BN1 9QH, England
email: luca@cogs.sussex.ac.uk
Abstract
Many process algebras are defined by structural operational semantics (SOS). Indeed, most
such definitions are nicely structured and fit the GSOS format of [13]. In [2] B. Bloom, F.
Vaandrager and I presented a procedure for converting any GSOS language definition to a finite
complete equational axiom system which precisely characterizes strong bisimulation of processes.
For recursion theoretic reasons, such a complete equational axiom system included, in general,
one infinitary induction principle  essentially a reformulation of the Approximation Induction
Principle (AIP) [7, 6].
However, it is wellknown that AIP and other infinitary proof rules are not necessary for
the axiomatization of, e.g., strong bisimulation over regular behaviours (see [29, 8, 31]). In
this paper, following [1], I characterize a class of infinitary GSOS specifications, obtained by
relaxing some of the finiteness constraints of the original format of Bloom, Istrail and Meyer,
which generate regular processes. I then show how the techniques of [2] can be adapted to give a
