I am a mathematician, and the worst that I can say is that, if I were writing for a mathematical audience, I might have phrased some things slightly differently. (Oh, and the title should be "as simply as possible", not "as simply as possible.") I didn't know the GJK algorithm before, but, if I were teaching Calculus III now, I'd probably see if I could find a way to work this in. That's how good your explanation is.