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Assuming only that if aliens exist then Bigfoot exists, and that an alien exists, proving Bigfoot exists. The proof says it's correct.

Logic was a really great class and I can really appreciate the sneaky exercises that are not at all obvious without lots of thought and sometimes a push through by one of the experts, the professor or the teacher's aid.

There are a lot of subtleties, for example, I tried the Bigfoot alien proof another way only to realize it couldn't work that way because of the subtleties of the requirements of each reason in the proof:

That just shows lizard people exist, based on the assumption an alien implies Bigfoot and aliens exist. Not really, I'm just being silly, but it's fun to wish it could. 

What I was trying to do was implicate Bf by instantiating ExLx into La but every time I existentially instantiated ExBx out of Bf out of La it didn't work. I think because of what it seems like, one thing implying another thing plus that something exists does not imply the one thing that is needed to make the modus ponens. In other words, ExLx doesn't imply La, but that wasn't particularly clear to me until I embarked on this proof for humor's sake. The point is that there are a lot of subtleties, and it is fun to put all the puzzle pieces together while learning the rules of logic as presented in this excellent course presented to us here at CSUMB.

For fun and to test my skills I proved DeMorgans's as side practice:

I would put more serious proofs, but I don't want to expose anything from the class.  These DeMorgans's proofs were for side practice.

Logic was a super useful class and I am extremely excited to have gotten through it. I really enjoyed all the exercises, especially the proofs, the English translation exercises, and what were called end-to-end exercises, the ones you go from English to logical language translation to proving if the argument presented is a valid logical argument or not and back to English stating whether the argument is valid or not. Imagine busting that out during a debate.

Next, assuming only that ( Fb->Pp ) -> Gp & Fb -> Pp I will show with crystal clarity that Gp:

Clearly, Gp.

That is just silly, but proofs are a lot of fun and extremely useful, so I am extremely excited to have learned the knowledge from the class. The lectures were clear and inspiring and showed not just the material but also how easy the proofs are once you understand all the methodology.