# HG changeset patch # User nipkow # Date 1536681188 -7200 # Node ID b0dfe57dfa09d42f1f37ecb12002c551e491e68f # Parent 7a9118e63cad2f5515d6478aa7da3c6c563150a0 "undefined" not needed, [] is perfectly natural diff -r 7a9118e63cad -r b0dfe57dfa09 src/HOL/Data_Structures/Sorting.thy --- a/src/HOL/Data_Structures/Sorting.thy Tue Sep 11 14:56:45 2018 +0200 +++ b/src/HOL/Data_Structures/Sorting.thy Tue Sep 11 17:53:08 2018 +0200 @@ -259,7 +259,7 @@ by (induction xs rule: merge_adj.induct) auto fun merge_all :: "('a::linorder) list list \ 'a list" where -"merge_all [] = undefined" | +"merge_all [] = []" | "merge_all [xs] = xs" | "merge_all xss = merge_all (merge_adj xss)"