A rule of inference used in prepositional logic. It is often abbreviated to 'Trans' for short.

(P→Q) = (¬Q →¬P)
If P, then Q is the same as If 'not Q' than 'not P'.
And, of course, vice versa.

Think about it. Think hard. And when that doesn't work, construct a Truth Table.

Oi. Okay, look. If P happens, then Q happens. That's the (P→Q) bit. So, if Q didn't happen, you know for a fact that P didn't happen, right? Cause if it did, you would have Q. So, not Q, then not P.


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