src/HOL/Data_Structures/Lookup2.thy
changeset 68413 b56ed5010e69
parent 67965 aaa31cd0caef
     1.1 --- a/src/HOL/Data_Structures/Lookup2.thy	Mon Jun 11 08:15:43 2018 +0200
     1.2 +++ b/src/HOL/Data_Structures/Lookup2.thy	Mon Jun 11 16:29:27 2018 +0200
     1.3 @@ -11,7 +11,7 @@
     1.4  
     1.5  fun lookup :: "('a::linorder * 'b, 'c) tree \<Rightarrow> 'a \<Rightarrow> 'b option" where
     1.6  "lookup Leaf x = None" |
     1.7 -"lookup (Node _ l (a,b) r) x =
     1.8 +"lookup (Node l (a,b) _ r) x =
     1.9    (case cmp x a of LT \<Rightarrow> lookup l x | GT \<Rightarrow> lookup r x | EQ \<Rightarrow> Some b)"
    1.10  
    1.11  lemma lookup_map_of: