I'm stuck with a big proof in my homework. I have to use natural deduction to prove something, and I think if I can prove this somehow then I can finish the full proof. Can anyone help?
P v Q, ¬P : Q
I have to do it from first principles though, I can't use DM's laws.
I can use the following rules:
implication intro, implication elim, conjunction intro, conjunction elim, disjunction intro, disjunction elim, (double) negation elimination, negation introduction (using Reductio Ad Absurdum)