Interesting problem and I appreciate the author bringing it to our attention. That said, I have to admit I found the Math Overflow post he took the solution fro

Interesting problem and I appreciate the author bringing it to our attention. That said, I have to admit I found the Math Overflow post he took the solution from much clearer: https://math.stackexchange.com/a/80743/ https://math.stackexchange.com/a/80743/ For one thing, the Math Overflow post is correct, whereas the blog post states a crucial inequality in the wrong direction. This confuses the whole argument, since the surrounding text isn't clear enough for the reader to easily self-correct the typo. The other factor is the flow of the exposition. For example, the blog post attempts to define Q before using it, but the definition is too vague and ends up being less useful than the "define in the course of the argument" approach used in the Math Overflow post.