What does this mean? Whats the difference between IFF and IF?
Logical implication A -> B can be expressed as if A then B.
A -> B and B -> A can be expressed as iff A then B.
Oh, I see now.
A<->B is iff
and A->B is if
Another way to think about it is that [itex]A \Leftrightarrow B[/itex] means that [itex]A[/itex] and [itex]B[/itex] have the same truth value. Either both are true or both are false.
If you are asked to do a proof of an IFF statement, you should break it down into two proofs: one of [itex]A \Rightarrow B[/itex] and the other of [itex]B \Rightarrow A[/itex]. Typically one direction will be easier than the other.
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