> But how do you encode stand-alone assertions like “all unitary matrices are invertible”? You could encode that as a yes-or-no question, but that’s useless, because rationally you can expect such questions to be biased towards yes.

If you're mostly trying to memorize that true implications are true, sure. But the answer to the converse question "Are all invertible matrices unitary?" is "no."

But memorizing the stronger statement that a unitary matrix U has inverse U* is more useful anyway.