A couple of disparate items, each of which I thought were quite instructional in their own ways…:

**1)**One of the lovely things about mathematics is that simple-sounding problems/puzzles may nonetheless lead to sharp disagreements over the correct answer (the Monty Hall puzzle being a classic example of this), but with little more than pencil and pad, the disagree-ers can talk through the differences, reaching agreement and an AHA! moment… no ill feelings had, just the enjoyment of learning and thinking! (…now if only cosmology was that simple!).

Anyway, if you follow mathy things on Twitter you may have seen the recent back-and-forth-and-back-again dispute over a recent Paul Krugman blog post in the

**NY Times**in which Krugman nonchalantly gave the answer to a conundrum dealing with traffic flow.

http://krugman.blogs.nytimes.com/2013/07/26/friday-night-music-sprawl-again/?_r=0

A certain mathematician of some repute, who we shan't name, but will simply call Stefanovich Stroganoff ;-) took issue with Krugman's answer on Twitter (and was quickly warned by some that questioning Krugman on math matters was playing with fire -- there were also many replies/comments directly to the post itself in the

**Times**). What followed were many more tweets debating the proper approach to the problem (fascinating that a mathematical debate can even be carried out in 140 characters or less!).

Anyway, in the end (given certain assumptions) Krugman's answer was vindicated after-all (the last tweet I recall from Stefanovich was hashtagged #EggOnFace), and Krugman himself responded with another short

**NY Times**piece about 48 hrs. later:

http://krugman.blogs.nytimes.com/2013/07/28/life-in-the-slow-lane-trivial/

A good time was had by all, I do believe… and now further, a Cornell engineering student has put up a longer piece (pdf) recounting the whole affair with fuller explanation of the mathematics involved:

http://ruina.tam.cornell.edu/research/topics/miscellaneous/KrugmanTraffic.pdf

**2)**Meanwhile, and a bit heavier than the above, over at

**Huffington Post**, of all places, there is a very good (...as far as I can tell) elucidation of the ABC conjecture for anyone wishing to read more on that subject that was brought into the limelight about a year ago by Shinichi Mochizuki:

http://www.huffingtonpost.com/shunsuke-katayama/abc-conjecture_b_3352657.html

## 1 comment:

Small correction:

I was an engineering student, but I am not one any more.

-Andy Ruina

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