User blog comment:Googleaarex/Extended Up Arrow Notation/@comment-24509095-20140331143502/@comment-24509095-20140331154519

It's either that the formalism just makes it erroneous or that it is, by itself, erroneous.

If the former is true, the rules of the notation must be very clear in his mind.

But, if the latter is true, Aarex probably didn't explore it very well (like my FGH Things).