src/HOL/Tools/function_package/fundef_package.ML

 
 (* outer syntax *)
 
 local structure P = OuterParse and K = OuterKeyword in
 
-val _ = OuterSyntax.keywords ["sequential", "otherwise"];
+val _ = OuterSyntax.keywords ["otherwise"];
 
 val _ =
   OuterSyntax.command "function" "define general recursive functions" K.thy_goal
   (fundef_parser default_config
      >> (fn ((config, fixes), (flags, statements)) =>