Divisor Relation is Antisymmetric/Corollary/Proof 2

Corollary to Divisor Relation is Antisymmetric
Let $a, b \in \Z$.

If $a \mathop \backslash b$ and $b \mathop \backslash a$ then $a = b$ or $a = -b$.

Proof
Let $a \mathop \backslash b$ and $b \mathop \backslash a$.

Then:
 * $\exists c, d \in \Z: a c = b, b d = a$

Thus: