Section PlusWf.
Variable A: Type.
Variable X: Set.
Variable Y: Type.
Variable TX: reduction_t A X.
Variable TY: reduction_t A Y.
Variable B: relation X.
Hypothesis HB: evolve TX TX B (plus B).
Hypothesis HB': well_founded (trans B).

(** Theorem 3.11 *)
Theorem plus_wf_controlled: controlled TX TY B.