is mentioned by

Def term_types(ds;da;de;t) == iterate(statevar x- > dec_lookup(ds;x) statevar x'- > dec_lookup(ds;x) funsymbol op- > < de.fun(op) > freevar x- > da trace(P)- > < lbl_pr( < Trace, P > ) > c1(c2)- > st_app(c1;c2) over t)

[term_types]

In prior sections: mb automata 2

Try larger context: GenAutomata