Abstraction and Empty Process in Process Algebra 1

Abstract

In this paper, we combine the hidden step η of the authors’ paper [2] with the empty process ε of VRANCKEN [12] and the authors’ [3]. We formulate a system ACPc, which is a conservative extension of the systems ACP _η , ACP√, but also of ACP _τ . This is a general system, in which most relevant issues can be discussed. Abstraction from internal steps can be achieved in two ways, in two stages: we can abstract to the hidden step η, and then from η to Milner’s silent step τ.