Homework 2


Question 1
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(A and B are propositions) is satisfiable.


Question 2
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(A and B are propositions) is unsatisfiable.


Question 3
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A, B are propositions, we have


Question 4
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Question 5
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These 4 sentences are all equivalent to each other


Question 6
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The expression: is in CNF form.


Question 7
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The clauses in the expression: are all in Horn form.


Question 8
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Sentence: entails Sunny


Question 9
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Sentence: is correct.


Question 10
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Choose all the correct options:


Question 11
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Consider the sentence in first order logic: HeightOf(X) (where X is a variable). Is the syntax of the expression correct in first order logic? Yes or No


Question 12
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Consider the sentence in first order logic: (where x,y are variables). Is the syntax of the expression correct in first order logic? Yes or No


Question 13
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The sentence in first order logic capture the English meaning: "Any small orange costs less than any large orange":


Question 14
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The sentence in first order logic capture the English meaning: "There is an animal that is cute and lazy":


Question 15
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The sentence in first order logic capture the English meaning: "All the pandas are cute and lazy":


Question 16
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The sentence in first order logic capture the English meaning:

"Every student in your school has a computer or has a friend who has a computer."

(The domain for both x and y consists of all students in your school.)

Explanation

See "Discrete Mathematics and Its Applications" page 61.


Question 17
?/? point (graded)

The sentence in first order logic capture the English meaning:

"There does not exist a woman who has taken a flight on every airline in the world."

where means “w has taken f”, and means “f is a flight on a.”. The domains of discourse for consist of all the women in the world, all airplane flights, and all airlines, respectively.

Explanation

See "Discrete Mathematics and Its Applications" page 63.


Question 18
?/? point (graded)

Use resolution to solve the following problem:

The knowledge base:

The query:

Does the knowledge base entail the query?