Definition

contrapositive

noun
  1. A statement formed by negating both the hypothesis and conclusion of a conditional statement and reversing their order; logically equivalent to the original statement.
  2. Usage: logic and mathematics; If the original statement is 'If P, then Q,' the contrapositive is 'If not Q, then not P.'
adjective
  1. Relating to or denoting a contrapositive statement or relationship.
  2. Usage: logic and mathematics

Examples

  • The contrapositive of 'If it rains, the ground is wet' is 'If the ground is not wet, it did not rain.'
  • In logic, a statement and its contrapositive are always logically equivalent.
  • To prove a theorem, mathematicians sometimes use the contrapositive approach instead of direct proof.
  • The contrapositive relationship is useful in geometry proofs.
  • Understanding the contrapositive helps students master conditional logic.
  • If the original implication is true, then the contrapositive must also be true.

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