Unsorting(randomizing) a sequence

[Tom Loredo]

Charles G Waldman wrote:
> 

> Correct.  However, I'm curious, what is the definition of a "perfect
> shuffle"?  

It's not a computer science article, and thus not completely relevant
to this thread, but if you want to learn more than you'll ever need
to know about the statistics of shuffling, Persi Diaconis is the man.
A standard reference is:

Trailing the Dovetail Shuffle to Its Lair",
by Dave Bayer & Persi Diaconis,  Annals App. Prob, Vol 2 # 2, May 1992, p 294.

This is the fellow who worked out the item reported in the popular press
a few years ago that it takes 7 shuffles to adequately shuffle a deck
of 52 cards.

Peace,
Tom Loredo