1. The problem statement, all variables and given/known data
I don't have symbols for negations, so i'll just use the word NOT..
Prove the validity of the sequents below:
NOT ( P -> Q) YIELDS Q-> P
2. Relevant equations
Relavent deductions as listed here.. http://en.wikipedia.org/wiki/Propositional_logic
Using things such as ^ elimination/introduction, Modens Ponens,.. etc
3. The attempt at a solution
1. NOT ( P -> Q) Premise
2. NOT Q Assumption
3. NOT NOT P MT 1,2 (added in extra negation from line 1)
4. P NOT NOT Elimination
5. NOT Q -> P
I"m looking for Q -> P.. which the opposite answer.. i think its something to do with the negations being all wrong.. any help??