Hey Rajeev

That's not the answer, that's the question. The authors of the textbook use a slightly different notation to that used by Gutenplan from COS161.

To translate:

let P = Max is home

let Q = Claire is home

let R = Carl is happy

Then by Gutenplan's notation, the question becomes

P v Q, Ã‚Â¬P v R, Ã‚Â¬Q v R |- R

The question requires an informal proof which is just basically using ordinary english to create the proof. The textbook give the following as an example of an informal proof:

Since Socrates is a man and all men are mortal, it follows that Socrates is mortal. But all mortals will eventually die, since that is what it means to be mortal. So Socrates will eventually die. But we are given that everyone who will eventually die sometimes worries about it. Hence Socreates sometimes worries about dying.

Hope this helps.

Rob