Mathematical Principle

Discuss your favorite close-up tricks and methods.

Postby Harry Lorayne » 03/12/07 08:29 PM

Can someone save me looking-up time? What's the mathematical principle where a spec. runs through an entire shuffled deck, counts to a thought-of number from 1 to 10. When he's finished you can tell him the number he started with. It's named after a physicist who's name starts with a K. Yhanks. HARRY LORAYNE.
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Postby Guest » 03/12/07 08:58 PM

It's the Kruskal Count, by Martin J. Kruskal...

(Thanks, Harry. I think of you every time I write ellipses...)

Postby David Scollnik » 03/12/07 09:12 PM

"Card Concepts" says Martin D. Kruskal was a Professor of Mathematics at Princeton. (I'm not vouching for the accuracy of Card Concepts, I'm just saying ... )

Harry may well be referring to the Kruskal principle but it didn't sound like it to me, not exactly.

I know of the Kruskal principle as the one where you count down in a deck the value of a card, then you count down again using the card you counted to, and you repeat this until you get as far in the deck as you can go without running out of cards.

The Kruskal principle is that the ending card will usually be the same regardless of the starting card used, as the different possible paths you could have taken tend to converge.

Perhaps this principle has been modified to get the effect HL described, I do not know.
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Postby David Scollnik » 03/12/07 09:26 PM

The way HL described the effect, it sounds more like some variation of the (Alexander F.) Kraus principle to me. But perhaps I misunderstand his post.
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Postby jerry lazar » 03/12/07 09:27 PM

Kruskal concept also works for words ... in any passage, in any book!... Check it out, you'll fool yourself!... ... tnG=Search
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Postby Guest » 03/17/07 07:56 AM

Sadly, Kruskal passed away recently... I believe in the last month.

Postby Sir Ross » 03/26/07 01:20 PM

For those interested in more mathematical 'magic.' This website has some interesting math info. Just before the entry on Martin J. Kruskal (Kruskal Count), there's a link to a PDF article on another such trick from a mathematician. (written by Michael Kleber)

I was in the Carribean suntanning so I missed the original post...hope it's not too late.

be well all
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