[TruthShallSetYouFree]

Another would be:
If A, then B
Not B
Therefore, not A

That appears to utilize the same same logic that the CONTAPOSITIVE syllogism does. As in:

If you are in the Obama administration, then you are a liar.
You are not a liar.
Therefore, you are not in the Obama administration.

Is that correct?

[SoothingDave]

Yes, that is the contrapositive. That’s the term I learned for it.

[JoeRed]

Yep, that’s it. I haven’t heard the term “contrapositive” used before, but a quick search led me to this:

“The inference rule modus tollens, also known as the law of contrapositive, validates the inference from P implies Q and the contradictory of Q, to the contradictory of P.”

[hobbes1]

Studying under Peikoff.

Envious.