Find a formula for a function from Z set of integers to N se

Find a formula for a function from Z (set of integers) to N (set of natural numbers) that is a bijection.

Solution

A function f (from Z (set of integers) to N (set of natural numbers) ) is bijective if, for every y in N (set of natural numbers), there is exactly one x in Z (set of integers):

such that f(x) = y