Section Arg3.
Variable gf : rel3 T0 T1 T2 -> rel3 T0 T1 T2.
Arguments gf : clear implicits.

Theorem paco3_acc: forall
l r (OBG: forall rr (INC: r <3= rr) (CIH: l <3= rr), l <3= paco3 gf rr),
l <3= paco3 gf r.