Theorem: formulation of uniqueness?

Question

I wonder which formulation of the following statement is preferable? I understand they are equivalent, but which is considered clearer?

1. Suppose $A,B\geq2$ are natural numbers. If the groups $G_A$ and $G_B$ are isomorphic, then $A=B$.

2. The function $A\mapsto G_A$ is injective on the natural numbers $\geq2$.

3. Suppose $A,B\geq2$ are two distinct natural numbers. Then $G_A$ and $G_B$ are not isomorphic.

We of course define $G_A$ earlier in the works.

I don't quite like 2 as it's over-formalistic. But 1 and 3 are quite equivalent. I personally like 3 more, but my colleague somehow prefers 1. Is there any good reason to choose one or the other?

Answer 1

This similar to the two definitions of injective function.

I think that the third is more elegant, because there is no "if" and the statement is more direct, but the seceond is seems to be more confortable to use.

The way of Wikipedia is good: you can state your preferable statement and put the second right after that.