Global Instance Fintegral : (Integral_domain (Rcr:=Fcri)).

Lemma Cd_Cd_EqF : forall P Px1 Py1 Px2 Py2, Cd O E SS U1 U2 P (proj1_sig Px1) (proj1_sig Py1) -> Cd O E SS U1 U2 P (proj1_sig Px2) (proj1_sig Py2) -> Px1 =F= Px2 /\ Py1 =F= Py2.