more rules
authorhaftmann
Mon, 02 Dec 2019 17:15:17 +0000
changeset 71399 29e7c6d11cf1
parent 71398 d50a718ccf35
child 71400 0aaf16a0f7cc
more rules
src/HOL/ex/Word.thy
--- a/src/HOL/ex/Word.thy	Mon Dec 02 17:15:16 2019 +0000
+++ b/src/HOL/ex/Word.thy	Mon Dec 02 17:15:17 2019 +0000
@@ -267,6 +267,10 @@
 
 subsubsection \<open>Properties\<close>
 
+lemma exp_eq_zero_iff:
+  \<open>(2 :: 'a::len word) ^ n = 0 \<longleftrightarrow> LENGTH('a) \<le> n\<close>
+  by transfer simp
+
 
 subsubsection \<open>Division\<close>