--- a/src/HOL/Rings.thy Thu Feb 17 19:42:15 2022 +0000
+++ b/src/HOL/Rings.thy Thu Feb 17 19:42:16 2022 +0000
@@ -114,7 +114,7 @@
lemma split_of_bool [split]: "P (of_bool p) \<longleftrightarrow> (p \<longrightarrow> P 1) \<and> (\<not> p \<longrightarrow> P 0)"
by (cases p) simp_all
-lemma split_of_bool_asm [split]: "P (of_bool p) \<longleftrightarrow> \<not> (p \<and> \<not> P 1 \<or> \<not> p \<and> \<not> P 0)"
+lemma split_of_bool_asm: "P (of_bool p) \<longleftrightarrow> \<not> (p \<and> \<not> P 1 \<or> \<not> p \<and> \<not> P 0)"
by (cases p) simp_all
lemma of_bool_eq_0_iff [simp]: