úÎ!ë ç     Safe s decClass of decidable types.Lawa# should be a Proposition, i.e. the  answers should be unique.Note:& We'd want to have decidable equality :~:= here too, but that seems to be a deep dive into singletons.decDecidable (nullary) relations.decIntuitionistic negation.decWe can negate anything twice.*Double-negation elimination is inverse of  and generally impossible.dec/Triple negation can be reduced to a single one.decWeak contradiction. decA variant of contraposition. decFlip  branches. decShow .decShow $ Yes ()"Yes ()"decShow $ No id "No <toVoid>" decConvert  a to  a, forgetting the  evidence. decConvert  to , forgetting the evidence.dec  respects this ordering.Note: yet if you have p :: a and p ::  a, something is wrong.        dec-0.0.3-J3Of5Fns2FN1mALR1HZtLi Data.Type.Dec DecidabledecideDecYesNoNegtoNegNeg tripleNeg contradictcontrapositiondecNegdecShow decToMaybe decToBool$fOrdDec$fEqDecbase GHC.MaybeMaybeghc-prim GHC.TypesBool