Given (p ⇒ q) and (r ⇒ s), use Fitch to prove (p ∨ r ⇒ q ∨ s )

• April 17th 2013, 08:50 AM
Alea
Given (p ⇒ q) and (r ⇒ s), use Fitch to prove (p ∨ r ⇒ q ∨ s )
Given (pq) and (rs), use the Fitch System to prove (prqs)

p => q - premise
r => s - premise

Goal : p | r => q | s
• April 18th 2013, 12:17 AM
Lord Voldemort
Re: Given (p ⇒ q) and (r ⇒ s), use Fitch to prove (p ∨ r ⇒ q ∨ s )
Use the fact that p $\rightarrow$ q is logically equivalent to ~p ∨ q.