prove this prove that, prove left prove right

Had an interesting question in CS1231 paper today:

Prove that F : X > Y is one-to-one if and only if f(SnT) = f(S) n f(T), where S, T exists in the domain X.

Right.

Think think think.

Still thinking.

Okay, so I can’t figure it out (Redbull doesn’t make you smarter apparently). So I come up with some lame compositional story:

x exists in F(X) iff f(SnT) iff f(S) n f(T) iff f(S) and f(T). Therefore, etc, etc, etc, etc ……….. …………………….. …… ……………….. ………….. …………. ………………………. .. . ………….. ………… …………….. ……………. Hence, little red riding hood was eaten because the wolf was hungry.

I hope I pass. Please God, please let me pass this.