pure interface of class Interface

public abstract class Interface
  extends Printable
{
    public int[] vars;
    public int low;
    public int high;
    public Constraints con;
    public void print(Printer p);
    public Interface tensor(Interface i);
    public Interface empty();
    public Interface splitL(Obj Y,
                            Obj Z);
    public Interface splitR(Obj Y,
                            Obj Z);
    public int botOr(int x);
    public int topOr(int x);
    public Interface();
}