The biconditional PleftrightarrowQP \\leftrightarrow QPleftrightarrowQ is equivalent to:
(PrightarrowQ)land(QrightarrowP)(P \\rightarrow Q) \\land (Q \\rightarrow P)(PrightarrowQ)land(QrightarrowP)
(PlandQ)lor(negPlandnegQ)(P \\land Q) \\lor (\\neg P \\land \\neg Q)(PlandQ)lor(negPlandnegQ)
Neither a nor b
Both a and b