Section C.
Variables X Y: Type.
Variable TX: reduction_t A X.
Variable TY: reduction_t A Y.
Variables F G: function X X.
Hypothesis HF: wmonotonic TX TX F.
Hypothesis HG: wmonotonic TX TX G.

(** Chaining respects weak monotonicity *)
Lemma Chaining_wmon: wmonotonic TX TX (Chain F G).
Variable L: relation Y.