The officer said to the detective, “If John was at the scene of the crime, then he knows that Jean could not have done it.” “No, Columbo,” answered the detective, “that is not correct. John was at the scene of the crime and Jean did it.” Was the detective’s statement a correct negation of Columbo’s statement?

Understand the Problem. We are asking for the negation of a given statement, which we then wish to compare with the proposed negation.