src/HOL/Basic_BNF_LFPs.thy
changeset 59819 dbec7f33093d
parent 59141 9a5c2e9b001e
child 61076 bdc1e2f0a86a
--- a/src/HOL/Basic_BNF_LFPs.thy	Thu Mar 26 16:42:42 2015 +0100
+++ b/src/HOL/Basic_BNF_LFPs.thy	Thu Mar 26 17:10:24 2015 +0100
@@ -99,8 +99,7 @@
 
 declare prod.size[no_atp]
 
-lemma size_nat[simp, code]: "size (n\<Colon>nat) = n"
-  by (induct n) simp_all
+lemmas size_nat = size_nat_def
 
 hide_const (open) xtor ctor_rec