Yes, I know. My Weekly Words are sporadic. I’m working on that. Here’s one now:
A good one to follow up a priori, a corollary is a proposition that follows without any additional proof from one already proven.
I think of it like this: If I can say therefore, it’s probably a corollary. For example: A=B therefore it follows that A is not less than B or therefore it follows that A is not greater than B.
Generally, its use is reserved for things that are self-evident, like the statements above. But it is sometimes used where the logic is deductive, but hardly self-evident like:
One has a right to life, therefore one has a right to property in himself.
Property in oneself is corollary because it is essentially a restatement of right to life, but someone who is not familiar with the ideas and terms may have to mull it over a bit before he realizes it.
It gets harder. For example: I think therefore I am. Or I doubt therefore God exists.
Both I am and God exists are corollary statements in the sense that they are deductive reasoning and are implied by the axioms (I think and I doubt) that precede them. But for sure you’ll need to mull them over!