Section CombineGreeters.
Variables (l1 l2 : Label) (nodes : seq nid) (this : nid).
Variable (lab_disj : l2 != l1).
Definition gp1 := GreeterProtocol nodes l1.
Definition gp2 := GreeterProtocol nodes l2.
Definition V := (W l1 nodes) \+ (W l2 nodes).

Lemma validV : valid V.