Give an explicit definition of the bijection f from N onto Z described in A. 1. A.1 The set of Z of all integers is denumerable. To construct a bijection of N onto Z, we map 1 onto 0, we map the set of even natural numbers onto the set N of positive integers, and we map the set of odd natural numbers onto the negative integers. This mapping can be displayed by the enumeration: Z = {0, 1, -1, 2, -2, 3, -3, ...}