Sets


(set-card S)
returns the cardinality of the set S


(set-contains S e)
is true iff e belongs to S

(set-elementadd S e)
returns the set S union {e}



(set-remove S e)
returns the set S \ {e}


set-emptyset
returns the emptyset

(set-isempty? S)
is true iff the set S is empty


(set-union A B)
returns the union of A and B


(set-singleton e)
returns the set {e}


(set-include? A B)
is true if A is included in B


(set-equal? A B)
is true if A = B