The inverse of PrightarrowQP \\rightarrow QPrightarrowQ is:
PlandnegQP \\land \\neg QPlandnegQ
negQrightarrownegP\\neg Q \\rightarrow \\neg PnegQrightarrownegP
negPrightarrownegQ\\neg P \\rightarrow \\neg QnegPrightarrownegQ
QrightarrowPQ \\rightarrow PQrightarrowP