Unformatted text preview: A 2 is: 3. Degree of the formula A 1 is: , degree of the formula A 2 is: 4. Write all proper, nonatomic subformulas of A 1 . 5. Write all nonatomic subformulas of A 2 . 6. Find a restricted model and a restricted countermodel of A 2 . Use shorthand notation. Show work. 7. There are more then 3 possible restricted countermodels of A 2 . Justify. 8. There are more then 2 possible restricted models of A 2 . Justify your answer. 9. List 3 models and 2 countermodels for A 2 by extending the restricted model and the countermodel you have found in 6. to the set V AR of all variables. 10. There are possible models for A 2 . There are possible countermodels for A 2 . QUESTION 3 Show that  = (( ¬ a ∪ b ) ⇒ ((( c ∩ d ) ⇒ ¬ d ) ⇒ ( ¬ a ∪ b ))) 1...
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 Spring '08
 Bachmair,L
 Computer Science, Logic, natural language, nonatomic subformulas, possible restricted models, possible restricted countermodels, natural language statement

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