The proof indicates that where p q => q and p => q. It shows that both the statement p v q is given and p is given. So, steps 3 through 5 shows statements that logically follow from statements 1 and 2 which are given because it proves that written in double negation (p) v q => q , and implication p q => q, then both statements 1 and 2 would be true that p v q and p would always be q.

What type of prrof is this? And can someone briefly explain this proof?