[codepie]

As another user pointed out, why should be the chromatic polynomial of rectangle with deleted edge be: q^4 - 3q^3 + 2q^2 and not q * (q - 1)^3. A counter example: when q=2, we have two ways to color the rectangle with a deleted edge. Am I missing something?

I think fixating q as the number of possible ways to color the end points of the deleted edge leads to the wrong result.

[omaranto]

This article was "reprinted" from the original at Quanta Magazine. The original article has the correct answer of q(q-1)^3. (It was probably corrected after Wired "reprinted" it.)

https://www.quantamagazine.org/a-path-less-taken-to-the-peak...

[_asummers]

Indeed. At the bottom:

> Correction June 27, 2017: The original version of this article included an error in the calculation of the chromatic polynomial of a rectangle.