I am having difficulty understanding first order logic for advanced problems. Is there a good resource to learn more, or does it just take practice? This is the problem I don't know how to do.
Define Inf(S) in first order logic over the universe Natural Numbers.
Any ideas where to start, or the steps to do this?
HINT: A subset $S$ of the natural numbers is infinite if and only it has no largest member. (I’m assuming that your formal language includes either $<$ or $\le$.)