Fixpoint Qquadratic_sign (a b c d e f g h : Z) (p1 p2 : Qpositive) {struct p1} :
  forall (H_Qquadratic_sg_denom_nonzero : Qquadratic_sg_denom_nonzero e f g h p1 p2),
  Z * (Z * (Z * (Z * Z)) * (Z * (Z * (Z * Z))) * (Qpositive * Qpositive)).Scheme Qquadratic_sg_denom_nonzero_inv_dep :=
  Induction for Qquadratic_sg_denom_nonzero Sort Prop.

Lemma Qquadratic_sign_nRdL_One : forall (a b c d e f g h : Z) (p1 p2 : Qpositive) (H_Qquadratic_sg_denom_nonzero : Qquadratic_sg_denom_nonzero e f g h p1 p2) (l1 na nb nc nd : Z) (l3 : Qpositive) (H_Qhomographic_sg_denom_nonzero : Qhomographic_sg_denom_nonzero (e + f) (g + h) p1), (l1, (na, (nb, (nc, nd)), l3)) = Qhomographic_sign (a + b) (c + d) (e + f) (g + h) p1 H_Qhomographic_sg_denom_nonzero -> p1 <> One -> p2 = One -> Qquadratic_sign a b c d e f g h p1 p2 H_Qquadratic_sg_denom_nonzero = (l1, (0%Z, (na, (0%Z, nb)), (0%Z, (nc, (0%Z, nd))), (l3, One))).