Being a native Chinese speaker, I've been confused by the English expression "if and only if." I know it introduces a condition which is necessary as well as sufficient, but I just don't quite grasp it. To understand it completely, I probably need to review the knowledge of "necessary condition" and "sufficient condition".
Description
Being a native Chinese speaker, I've been confused by the English expression "if and only if." I know it introduces a condition which is necessary as well as sufficient, but I just don't quite grasp it. To understand it completely, I probably need to review the knowledge of "necessary condition" and "sufficient condition".