let rec convert_machines ((k1,e1,t1,s1 as m1),(k2,e2,t2,s2 as m2),delta) =
(alpha_eq test_eq_only
(R.unwind (k1,e1,t1,[])) (R.unwind (k2,e2,t2,[])) &&
let rec convert_machines ((k1,e1,t1,s1 as m1),(k2,e2,t2,s2 as m2),delta) =
(alpha_eq test_eq_only
(R.unwind (k1,e1,t1,[])) (R.unwind (k2,e2,t2,[])) &&