(** * Composition of simulation, expansion1, wexpansion1 relations *)
Section Composition.
Variables X Y Z: Type.
Variable TX: reduction_t A X.
Variable TY: reduction_t A Y.
Variable TZ: reduction_t A Z.
Variable R: relation2 X Y.
Variable S: relation2 Y Z.

Lemma simulation_comp: simulation TX TY R -> simulation TY TZ S -> simulation TX TZ (comp R S).