Translations between the frameworks 

Interval can be represented by its beginning and end;

  So some IRs can be represented by a conjunction of PRs on

  its margins;

  Example:

  x --->  (Bx, Ex)

  y --->  (By, Ey)

  x<y can be represented as : (Bx<Ex<By<Ey)

Number of indefinite IRs can be represented by a PR

  set