Consider the function $θ:\{0,1\}×{\Bbb N}→{\Bbb Z}$ defined as $θ(a,b)=(-1)^{a}b$

52 Views Asked by At

How do I prove the function $\theta$ is injective, surjective, and bijective, if any of these?

1

There are 1 best solutions below

0
On

$0$ is not in the range so it is not surjective. Can you see that it is injective? Hint: if $\theta (a,b)=\theta(a',b')$ take absolute value on both sides to prove that $b=b'$ and then prove that $a=a'$.