Section s_pulb_def.
Variables (A B C : Setoid) (f : Map A B) (g : Map C B).
Definition S_pulb_pred (axc : SPROD A C) :=
f (Sprod_l axc) =_S g (Sprod_r axc).
Canonical Structure S_pulb_constr := Build_Setoid_pred S_pulb_reg.
Definition S_pulb_prod := SubSetoid S_pulb_constr.
Definition S_pulb_p := RestrictedMap (Proj1_SPROD A C) S_pulb_constr.
Definition S_pulb_q := RestrictedMap (Proj2_SPROD A C) S_pulb_constr.

Lemma S_pulb_law1 : Pullback_law1 f g S_pulb_p S_pulb_q.