(* compute states occuring in transition candidates *)
let rec add_st (ql,qr) = function
| [] -> ql,qr
- | f :: tl -> let sql,sqr = Formula.st f in
+ | f :: tl -> let sqs,sql,sqr = Formula.st f in
let ql' = StateSet.union sql ql
and qr' = StateSet.union sqr qr in
add_st (ql',qr') tl in