Now Datatype.occs_in_prems prints the necessary warning ITSELF.
It is also easier to invoke and even works if the induction variable
is a parameter (rather than a free variable).
(* Title: HOL/Modelcheck/CTL.thy
ID: $Id$
Author: Olaf Mueller, Jan Philipps, Robert Sandner
Copyright 1997 TU Muenchen
*)
CTL = MuCalculus +
types
'a trans = "('a * 'a) set"
consts
CEX ::"['a trans,'a pred, 'a]=>bool"
EG ::"['a trans,'a pred]=> 'a pred"
defs
CEX_def "CEX N f u == (? v. (f v & (u,v):N))"
EG_def "EG N f == nu (% Q. % u.(f u & CEX N Q u))"
end