Subst/utlemmas.thy

+(*  Title: 	Substitutions/utermlemmas.thy
+    Author: 	Martin Coen, Cambridge University Computer Laboratory
+    Copyright   1993  University of Cambridge
+
+Additional definitions for uterms that are not part of the basic inductive definition.
+*)
+
+UTLemmas = UTerm + Setplus +
+
+consts
+
+  vars_of       ::   "'a uterm=>'a set"
+  "<:"          ::   "['a uterm,'a uterm]=>bool"   (infixl 54) 
+
+rules  (*Definitions*)
+
+  vars_of_def   "vars_of(t) == uterm_rec(t,%x.{x},%x.{},%u v q r.q Un r)"
+  occs_def      "s <: t == uterm_rec(t,%x.False,%x.False,%u v q r.s=u | s=v | q | r)"
+
+end