Date: Dec 9, 2012 11:29 PM
Subject: tautology of conditions

Hi, Im new to mathematica and I would like to know if there is some way to do tautology of conditions, with that i mean the following:
I have lets say:

1. p || q
2. p => r
3. q => s
r || s (conclusion)

And I have to prove this conclusion is right. How do I do that with mathematica? also is there any way I could see steps mathematica make to get the result ?