Easy. As soon as I saw "Inner Rim" I knew that implied "Outer Rim" and knew what it was.
Edit: Apparently Andy followed the same trail of thought.
Yes. Although, if you first see "core worlds" and "colonies" (as I did), you might be tempted to think this is from another popular science fiction series. Pretty easy to recognize where it's
really from when you look at the planet names, though.