Logical biconditional
= Logical biconditional
{title2=$P\leftrightarrow Q$}
A binary <logical connective> true exactly when its two arguments have the same <truth value>. It is <logically equivalent> to $(P\to Q)\land(Q\to P)$, and hence to $(\neg P\lor Q)\land(\neg Q\lor P)$. Its <truth table> has value one on input pairs $(0,0)$ and $(1,1)$, and zero on $(0,1)$ and $(1,0)$.