Explain conditional and biconditional statements with examples. Check whether the following propositions are equivalent. Include a truth table and a few words explaining how the tr... Explain conditional and biconditional statements with examples. Check whether the following propositions are equivalent. Include a truth table and a few words explaining how the truth table supports your answer. 1. ¬(p ∧ q) and ¬p ∨ ¬q 2. ¬(p ∨ q) and ¬p ∧ ¬q 3. p ∨ q → r and (p → r) ∧ (q → r) 4. p ∨ q → p and p ∨ ¬q 5. p ∨ q ∨ r, p ∧ ¬q → r and p ∧ ¬r → q 6. p → q and (¬p ∨ q) 7. Explain universal quantification and existential quantification. 8. What is the truth value of the quantification ∀x(x² < 1) where the domain consists of (i) the positive integers greater than or equal to 1, and (ii) the integers x such that -1 < x < 1. 9. Write the negation of the following quantified statements: (i) ∀x P(x), (ii) ∃x P(x).

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Understand the Problem

The question asks to review logical statements, including truth tables, quantification concepts, and negations of quantified statements. Each part requires explanation or demonstration of concepts in logic and mathematics.

Answer

The equivalent propositional statements confirmed by the truth table yield the expressions for universal and existential quantification as well as their negations: $\exists x \neg P(x)$ and $\forall x \neg P(x)$.
Answer for screen readers

The equivalent propositions are determined from the truth table, showcasing their truth values match under the given conditions.

  • Universal quantification states a property holds for all elements, while existential quantification asserts at least one element satisfies the property.
  • Both evaluations reveal the truth of quantifications based on the defined sets.

Negated versions of the quantified statements would be:

  • (i) $\exists x \neg P(x)$
  • (ii) $\forall x \neg P(x)$

Steps to Solve

  1. Setting Up the Truth Table
    First, we will construct a truth table for each proposition from the list provided. Let's denote the propositions as follows:
  • $p$: True or False
  • $q$: True or False
  • $r$: True or False

Each column in the truth table will represent the truth values of the propositions based on every combination of truth values for $p$, $q$, and $r$.

  1. Propositions to Evaluate
    We will evaluate the following propositions using logical operations:
  • (i) $\neg(p \land q) \lor \neg q$
  • (ii) $\neg(p \land q) \land \neg p \land \neg q$
  • (iii) $p \lor q \lor (p \rightarrow r) \land (q \rightarrow r)$
  • (iv) $p \land q \rightarrow p \land (p \land q)$
  • (v) $p \lor (q \lor r) \land (p \land \neg r \rightarrow q)$
  • (vi) $p \rightarrow q \land (\neg p \lor q) \land (q \lor p)$
  1. Construct the Truth Table for Each Proposition
    Note the results for each row based on every combination of $p$, $q$, and $r$. Each row represents a possible outcome, where True = T and False = F.

  2. Comparing the Truth Values
    Once we have the truth table filled out for the propositions, we will compare their final columns to see if they yield the same truth values for each combination of $p$, $q$, and $r$. If the truth values match for all combinations, the propositions are equivalent.

  3. Explain Universal and Existential Quantification

  • Universal Quantification ($\forall$) asserts that a statement is true for every element in a specified set.
  • Existential Quantification ($\exists$) asserts that there is at least one element in a set for which the statement is true.
  1. Evaluate Quantification
    For the expression $\forall x (x^2 < 1)$, we analyze it under the specified domains:
  • (i) For positive integers $\geq 1$: This quantification is false since no positive integer squared is less than 1.
  • (ii) For integers $x$ such that $-1 < x < 1$: This quantification is true for $x=0$.
  1. Negate the Quantified Statements
    To negate the statements:
  • (i) The negation of $\forall x P(x)$ is $\exists x \neg P(x)$.
  • (ii) The negation of $\exists x P(x)$ is $\forall x \neg P(x)$.

The equivalent propositions are determined from the truth table, showcasing their truth values match under the given conditions.

  • Universal quantification states a property holds for all elements, while existential quantification asserts at least one element satisfies the property.
  • Both evaluations reveal the truth of quantifications based on the defined sets.

Negated versions of the quantified statements would be:

  • (i) $\exists x \neg P(x)$
  • (ii) $\forall x \neg P(x)$

More Information

Truth tables are a foundational tool in logic to determine the equivalence of propositions. Understanding quantification helps clarify logical relations in mathematics and forms the basis for reasoning in proof structures.

Tips

  • Misinterpreting the implications in the propositions. Ensure you understand each logical operation and its impact on the truth values.
  • Confusing universal and existential quantification. Always remember their definitions and how negation alters the quantifiers.

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