 What was Brian Arthur’s claim to fame?
I wrote no such thing, and Arthur has never, to my knowledge, claimed any such thing. In effect, he is accusing Brian Arthur, a man he calls a "nice guy," of being a fabricator or a liar. Evidently, Krugman felt four years ago that Arthur's contribution was important enough to merit a prominent mention in his book. However, I am not so ignorant of the canons of journalism (and of common sense) that I would take a plausible fellow like Brian Arthur at face value without checking up on him.
 An economist who applied an understanding of increasing returns to high-technology markets.
 An economist who applied an understanding of increasing returns to high-technology markets.  The author of “Complexity.”  A founder of modern economics.  A scholar of international trade who was primarily responsible for the rediscovering of increasing returns.