fact: Definition ldiff a b := match norm_pos a, norm_pos b with | Pos a, Pos b => Pos (NN.ldiff a b) | Neg a, Pos b => Neg (NN.succ (NN.lor (NN.pred a) b)) | Pos a, Neg b => Pos (NN.land a (NN.pred b)) | Neg a, Neg b => Pos (NN.ldiff (NN.pred b) (NN.pred a)) end.
imports: ZArith Lia BigNumPrelude NSig ZSig