1.
Let AA be the set of all functions f:ZZf: \mathbb{Z} \to \mathbb{Z} and RR be a relation on AA such that R={(f,g)f(0)=g(1) and f(1)=g(0)}R = \{(f,g) \mid f(0) = g(1) \text{ and } f(1) = g(0)\}. Then RR is