From mu CRL to mCRL2

We sketch the language mCRL2, the successor of mu CRL, which is a process algebra with data, devised in 1990 to model and study the behaviour of interacting programs and systems. The language is improved in several respects guided by the experience obtained from numerous applications where realistic systems have been modelled and analysed. Just as with mu CRL, the leading principle is to provide a minimal set of primitives that allow effective specifications, that conform to standard mathematics and that allow standard mathematical manipulations and proof methodologies. In the first place the equational abstract datatypes have been enhanced with higher-order constructs and standard data types, ranging from booleans, numbers and lists to sets, bags and higher-order function types. In the second place multi-actions have been introduced to allow a seamless integration with Petri nets. In the last place communication is made local to enable compositionality.