diff -r 46f59511b7bb -r d97fdabd9e2b src/HOL/Algebra/Exact_Sequence.thy
--- a/src/HOL/Algebra/Exact_Sequence.thy	Fri Sep 20 19:07:10 2024 +0200
+++ b/src/HOL/Algebra/Exact_Sequence.thy	Fri Sep 20 19:51:08 2024 +0200
@@ -22,7 +22,7 @@
 
 abbreviation exact_seq_arrow ::
   "('a \<Rightarrow> 'a) \<Rightarrow> 'a monoid list \<times> ('a \<Rightarrow> 'a) list \<Rightarrow>  'a monoid \<Rightarrow> 'a monoid list \<times> ('a \<Rightarrow> 'a) list"
-  ("(3_ / \<longlongrightarrow>\<index> _)" [1000, 60])
+  (\<open>(3_ / \<longlongrightarrow>\<index> _)\<close> [1000, 60])
   where "exact_seq_arrow  f t G \<equiv> (G # (fst t), f # (snd t))"