Discrete Mathematics


Q221.

Which of the following first order formulae is logically valid? Here \alpha(x) is a first order formula with x as a free variable, and \beta is a first order formula with no free variable.
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Q222.

P and Q are two propositions. Which of the following logical expressions are equivalent? I. P\vee \sim Q II.\sim (\sim P \wedge Q) III.(P \wedge Q)\vee (P\wedge \sim Q)\vee (\sim P\wedge \sim Q) IV. (P\wedge Q)\vee \vee (P\wedge \sim Q)\vee (\sim P\wedge Q)
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Q223.

Identify the correct translation into logical notation of the following assertion. Some boys in the class are taller than all the girls Note: taller (x, y) is true if x is taller than y.
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Q224.

Consider the following first order logic formula in which R is a binary relation symbol. \forall x \forall y(R(x, y) \Longrightarrow R(y, x)),The formula is
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Q225.

Let P(x) and Q(x) be arbitrary predicates. Which of the following statements is always TRUE?
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Q226.

Which one of the first order predicate calculus statements given below correctly expresses the following English statement? Tigers and lions attack if they are hungry or threatened.
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Q227.

Which one of these first-order logic formulae is valid?
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Q228.

Consider the following propositional statements: P1:((A\wedge B)\rightarrow C)\equiv (A\rightarrow C)\wedge (B\rightarrow C) P2:((A\vee B)\rightarrow C)\equiv (A\rightarrow C)\vee (B\rightarrow C) Which one of the following is true?
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Q229.

Let Graph(x) be a predicate which denotes that x is a graph. Let Connected(x) be a predicate which denotes that x is connected. Which of the following first order logic sentences DOES NOT represent the statement: "Not every graph is connected"?
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Q230.

What is the first order predicate calculus statement equivalent to the following? Every teacher is liked by some student
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