# coding=utf-8 id = 133 name = 'subset/2' slug = 'generate all subsets of a set' description = '''\

subset(Set, Subset): the set Subset is a subset of Set. This predicate should generate all valid solutions, one by one.

  ?- subset([1,2,3], SS).
    SS = [1,2,3] ;
    SS = [1,2] ;
    SS = [1,3] ;
    SS = [1] ;
    SS = [2,3] ;
    SS = [2] ;
    SS = [3] ;
    SS = [].
''' hint = {}