don't use readable names if proof reconstruction is needed, because it uses the structure of names
(*<*)
theory unfoldnested imports Main begin;
(*>*)
datatype ('v,'f)"term" = Var 'v | App 'f "('v,'f)term_list"
and ('v,'f)term_list = Nil | Cons "('v,'f)term" "('v,'f)term_list"
(*<*)
end
(*>*)