Conditional Proof

Me in my office when students don't come in and I know some don't understand what's going on.
Agenda
1. Notes on the test.

• DN Rule 
• Assumption column 

2. CP Rule

Extra practice with DN, MP, MT, &In, &Out
You should be able to do these.

Conditional Proofs (CP rule)
How to do conditional proof:
Sing the following:
Started from the bottom, now we're here.
Started from the bottom, put the antecedent up here.

Proofs are solved not only from the top down (e.g., DN, MP, MT, &In, &Out) but also bottom up. We work from both ends. CP proof is what's known as a "bottom up" rule.

Practice (CP only)
A.

1. Q /:. P>Q

B.

1. R /:. P>(Q>R)

C. 

1. T /:. P>(Q>(~R>(S>(~T>(U>V)))))

D. (This proof isn't *only* CP)

1. /:. (A&B)>(C>B)

Putting It All Together: Proofs with CP, DN, MT, MP, &In, &Out
A.

1. A>~B
2. B
3. (A>~B)>C  /:. B>(D>(~A&C))