Inverse of a Theorem

Inverse of a Theorem

 

the theorem obtained when the hypothesis and conclusion of a given initial theorem are replaced by their negations. For example, the theorem “If the sum of the opposite angles of a quadrangle is equal to 180°, a circle can be circumscribed about the quadrangle” has the inverse “If the sum of the opposite angles of a quadrangle is not equal to 180°, a circle cannot be circumscribed about the quadrangle.” The inverse of a theorem is equivalent to the theorem’s converse.