How is it possible to get the following (swi-)prolog predicate:
union( ListOfLists, -ResultList)
in the form:
ListOfLists = [A1, A2, A3, ..., An]
ResultList = A1 ∪ A2 ∪ A3 ∪ ... ∪ An
CodePudding user response:
If your "union" is commutative and if the identity element is the empty set, you could trivially define:
union(Ls, U, Op, Empty) :-
foldl(Op, Ls, Empty, U).
How do you represent your union? If it is a list, then []
is the empty set, and if you already have a union/3
defined (where the last argument is the union of the first two), then:
union(Ls, U) :-
foldl(union, Ls, [], U).
But what is the computational complexity of your union/3
?