changeset 79544 | 50ee2921da94 |
parent 77172 | 816959264c32 |
child 80084 | 173548e4d5d0 |
--- a/src/HOL/GCD.thy Mon Jan 29 21:18:11 2024 +0100 +++ b/src/HOL/GCD.thy Tue Jan 30 16:39:21 2024 +0000 @@ -2942,4 +2942,11 @@ in [(\<^const_syntax>\<open>semiring_char\<close>, char_type_tr')] end \<close> + +lemma CHAR_not_1 [simp]: "CHAR('a :: {semiring_1, zero_neq_one}) \<noteq> Suc 0" + by (metis One_nat_def of_nat_1 of_nat_CHAR zero_neq_one) + +lemma (in idom) CHAR_not_1' [simp]: "CHAR('a) \<noteq> Suc 0" + using local.of_nat_CHAR by fastforce + end