diff -r 0e6adce08fb0 -r d8f5d3391766 src/Provers/Arith/cancel_numeral_factor.ML
--- a/src/Provers/Arith/cancel_numeral_factor.ML	Thu Aug 08 23:48:31 2002 +0200
+++ b/src/Provers/Arith/cancel_numeral_factor.ML	Thu Aug 08 23:49:44 2002 +0200
@@ -30,7 +30,7 @@
                              as with < and <= but not = and div*)
   (*proof tools*)
   val prove_conv: tactic list -> Sign.sg -> 
-                  thm list -> term * term -> thm option
+                  thm list -> string list -> term * term -> thm option
   val trans_tac: thm option -> tactic (*applies the initial lemma*)
   val norm_tac: tactic                (*proves the initial lemma*)
   val numeral_simp_tac: tactic        (*proves the final theorem*)
@@ -53,10 +53,7 @@
 (*the simplification procedure*)
 fun proc sg hyps t =
   let (*first freeze any Vars in the term to prevent flex-flex problems*)
-      val rand_s = gensym"_"
-      fun mk_inst (var as Var((a,i),T))  = 
-	    (var,  Free((a ^ rand_s ^ string_of_int i), T))
-      val t' = subst_atomic (map mk_inst (term_vars t)) t
+      val (t', xs) = Term.adhoc_freeze_vars t;
       val (t1,t2) = Data.dest_bal t' 
       val (m1, t1') = Data.dest_coeff t1
       and (m2, t2') = Data.dest_coeff t2
@@ -73,13 +70,13 @@
                 else Data.mk_bal (Data.mk_coeff(n1,t1'), Data.mk_coeff(n2,t2'))
       val reshape =  (*Move d to the front and put the rest into standard form
 		       i * #m * j == #d * (#n * (j * k)) *)
-	    Data.prove_conv [Data.norm_tac] sg hyps 
+	    Data.prove_conv [Data.norm_tac] sg hyps xs
 	      (t',   Data.mk_bal (newshape(n1,t1'), newshape(n2,t2')))
   in
       apsome Data.simplify_meta_eq
        (Data.prove_conv 
 	       [Data.trans_tac reshape, rtac Data.cancel 1,
-		Data.numeral_simp_tac] sg hyps (t', rhs))
+		Data.numeral_simp_tac] sg hyps xs (t', rhs))
   end
   handle TERM _ => None
        | TYPE _ => None;   (*Typically (if thy doesn't include Numeral)