doc-src/Intro/list.thy

new method "elim_to_cases" provides ad-hoc conversion of obtain-style
elimination goals to a disjunction of existentials.

List = FOL +
types 	list 1
arities list	:: (term)term
consts	Nil	:: "'a list"
   	Cons	:: "['a, 'a list] => 'a list" 
end