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INTRO LOGIC. Derivations in SL 5. DAY 13. Exam 2 Format. 6 argument forms, 15 points each, plus 10 free points Symbolic argument forms (no translations) For each one, you will be asked to construct a derivation of the conclusion from the premises. The rule sheet will be provided.
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INTRO LOGIC Derivations in SL5 DAY 13
Exam 2 Format • 6 argument forms, 15 points each, plus 10 free points • Symbolic argument forms (no translations) • For each one, you will be asked to construct a derivation of the conclusion from the premises. • The rule sheet will be provided. • 1 problem from Set D • 2 problem from Set E • 2 problems from Set F • 1 problem from Set G (91-96)
Inference Rules (so far) &O (&) –––––––– &O & –––––– & –––––– &I –––––– & –––––– & O –––––– –––––– I –––––– –––––– O () –––––––– O –––––– –––––– O () –––––––– & DN ––––– ––––– I ––––
Rules (so far) DD : DD CD : CDAs: D : DAs: ID : IDAs:
SHOW-STRATEGIES • There are 6 kinds of formulas in Sentential Logic: 1. atomic formulas P, Q, etc. 2. negations 3. conjunctions & 4. conditionals 5. disjunctions 6. biconditionals For each of these, there is a suggested show-strategy.
Show-Conditional Strategy • : • As • : • ° • ° • ° CD ??
Show-Negation Strategy • : • As • : • ° • ° • D DD
Show-Atomic Strategy • : • As • : • ° • ° • ID DD is atomic (P,Q,R, etc.)
Show-Disjunction Strategy • : • [] As • : • ° • ° • ID DD
Show-Conjunction Strategy &D • : & • : • ° • ° • ° • : • ° • ° • ° ?? ?? NEW RULENEW STRATEGY
Example 1 (1) P (Q & R) Pr (2) : (P Q) & (P R) &D (3) : P Q CD (4) P As (5) : Q DD (6) Q & R 1,4, O (7) Q 6, &O (8) : P R CD (9) P As (10) : R DD (11) Q & R 1,9, O (12) R 11, &O
Example 2 (1) P Q Pr (2) Q P Pr (3) Q P Pr (4) : P & Q &D (5) : P D (6) P As (7) : DD (8) Q 1,6, O (9) P 3,8, O (10) 6,9, I (11) : Q D (12) Q As (13) : DD (14) P 2,12, O (15) P 3,12, O (16) 14,15, I
Example 3 (1) P Q Pr (2) P Q Pr (3) : (P Q) (Q & P) CD (4) P Q As (5) : Q & P &D (6) : Q ID (7) Q As (8) : DD (9) P 1,7, O (10) Q 4,9, O (11) 7,10, I (12) : P ID (13) P As (14) : DD (15) Q 2,13, O (16) P 4,15, O (17) 13,16, I