public void ElementaryRelationTest() { var s = new Set <int>(); s.Add(2); s.Add(4); var l = new List <OrderedTuple2 <int> >(); l.Add(new OrderedTuple2 <int>(2, 4)); s.AddRelationExtension <Relation2 <int> >(l); Assert.IsTrue(s.Is(2, 4)); }