The Mathematics of Paul Krugman

Paul Krugman on Paul Krugman:

My first love was history; I studied little math, picking up what I needed as I went along...
Always try to express your ideas in the simplest possible model...
I have used the "minimum necessary model" approach over and over again... In each case the effect has been to allow me to tackle a subject widely viewed as formidably difficult with what appears, at first sight, to be ridiculous simplicity.
The downside of this strategy is, of course, that many of your colleagues will tend to assume that an insight that can be expressed in a cute little model must be trivial and obvious... There is a special delight in managing not only to boldly go where no economist has gone before, but to do so in a way that seems after the fact to be almost childs' play.

Ryan Avent on Paul Krugman:

What you don't see is that underneath the models Krugman contributed is a lot of very difficult math. I had always considered myself a math guy until I got into the math that's involved in basic graduate economics. Then I realized I was not a math guy. I remain wowed by the fact that this guy can deploy these crazy equations on the one hand and write so well on the other.
Back when I was first getting into economic geography, I read The Spatial Economy, which was co-written by Krugman, Masa Fujita, and LSE's Tony Venables. It develops some "basic" economic geography theory from the ground up, and it's fascinating reading-right up until they start dropping equations on you.