Definition monotone5 T0 T1 T2 T3 T4 (gf: rel5 T0 T1 T2 T3 T4 -> rel5 T0 T1 T2 T3 T4) :=
  forall x0 x1 x2 x3 x4 r r' (IN: gf r x0 x1 x2 x3 x4) (LE: r <5= r'), gf r' x0 x1 x2 x3 x4.

Theorem paco5_mon: monotone5 (paco5 gf).