The Rules of Inference
1. A⊃B
2. A /∴B
What is Modus Ponens?
I drank the poison. I took the antidote. Therefore, I both drank the poison and took the antidote.
What is Conjunction? (Conj.)
Affirming the antecedent.
What is Modus Ponens?
What statement goes at the end of a proof of validity?
What is Q.E.D.?
1. A /∴AvB
What is Addition? (Add.)
1. A⊃B /∴A⊃(A*B)
What is Absorption? (Abs.)
Denying the consequent
What is Modus Tollens?
When the initial problem is invalid.
What is "when do you do not need to continue with a formal proof?"
1. U
2. Z /∴U*Z
What is Conjunction? (Con.)
I can have either chicken or sea bass for dinner. I do not have the chicken, therefore I must have the sea bass.
What is a Disjunctive Syllogism? (D.S.)
A valid argument form which can be used to justify steps in a proof.
What is a rule of inference?
Skipping or combining steps.
What is "something we can never do with formal proofs of validity?"
1. Z*A /∴Z
What is Simplification? (Simp.)
If I do my chores, then my back will hurt, and If I stay in bed, then my parents will ground me. I either have to do my chores or stay in bed. Therefore, my back will either hurt, or I will be grounded.
A step-by-step deduction of a conclusion from a set of premises, each step being justified by an appropriate basic rule.
What is a formal proof of validity?
1. (AvB) ⊃ (YvZ)
2. ~(YvZ) /∴~(AvB)
What is Modus Tollens? (M.T.)
1.(AvB)⊃(CvD)
2.(CvD)⊃(EvF) /∴(AvB)⊃(EvF)
Quod erat demonstrandum
What is the Latin words making up Q.E.D.? Or "What was to be demonstrated."