Problem 4.1. let a, b and c be non-empty sets, r a relation from a to b, and s a relation from b to c. (1) prove dom(s r) c dom(r). (2) find a concrete counterexample for the statement dom(so r) = dom(r) . hint. (1) let x dom(so r). (and all you need to do is to show x e dom (r) .) (2) give a counterexample with concrete a, b, c, r and s. 21 .ah +hat