Skip to main content

Converse, inverse, contrapositive of prime statement

Short answer

Original: If a positive integer is prime then it has no divisors other than 1 and itself (p→q). Converse (q→p): If it has no such divisors then it is prime. Inverse (¬p→¬q): If not prime then it has another divisor. Contrapositive (¬q→¬p): If it has another divisor then it is not prime.

State the converse, contrapositive and inverse of the statement, "A positive integer is prime only if it has no divisors other than 1 and itself".

Let p: "a positive integer is prime" and q: "it has no divisors other than 1 and itself".

"p only if q" means p → q. So the given statement is: If a positive integer is prime, then it has no divisors other than 1 and itself.

FormSymbolicStatement
Converseq → pIf a positive integer has no divisors other than 1 and itself, then it is prime.
Inverse¬p → ¬qIf a positive integer is not prime, then it has a divisor other than 1 and itself.
Contrapositive¬q → ¬pIf a positive integer has a divisor other than 1 and itself, then it is not prime.

The contrapositive is logically equivalent to the original statement. The converse and the inverse are equivalent to each other, but not to the original statement in general.

✓ Answer checked by Claude Opus 5.5 (high effort)

All Discrete Structure chapter 1 questions →