type problem

val label_of_problem : problem -> string

type result = [
 | `Separable of (int * Num.nf) list
 | `Unseparable of string
]

val problem_of: (string (* problem label *)
* Num.i_var option (* div *)
* Num.i_n_var list (* conv *)
* Num.i_n_var list (* ps *)
* string list (* names of free variables *)) -> problem
val solve: problem -> result