chickadee » slset » slset<=

Returns true iff every LIST_i is a subset of LIST_i+1.

List A is a subset of list B if every symbol in A also occurs in B.

(slset<= '(a) '(a b a) '(a b c c)) => #t

(slset<= '(a b) '(a)) =>  #f
(slset<= '(a b) '(a c)) =>  #f

(slset<=) => #t             ; Trivial cases
(slset<= '(a)) => #t