SI
SI
discoversearch

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor.  We ask that you disable ad blocking while on Silicon Investor in the best interests of our community.  If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.
Pastimes : Dispatches from the Ivory Tower -- Ignore unavailable to you. Want to Upgrade?


To: exdaytrader76 who wrote (52)3/3/2005 10:28:02 AM
From: LPS5  Respond to of 79
 
German discovers longest prime number

by Luke Harding in Berlin
Wednesday March 2, 2005
The Guardian

A German eye specialist with a keen amateur interest in mathematics has discovered the world's largest prime number after a 50-day search using his personal computer.
Dr Martin Nowak, who has his own practice in the south German town of Michelfeld, stumbled upon the number last week, breaking the previous record for a prime number by half a million digits.

Prime numbers are divisible only by themselves and 1. While the first prime numbers 2, 3, 5, and 7, are easy to identify, Dr Nowak's monster prime number is more than 7.8m digits long and is written as 2 to the 25,964,951st power minus 1.

The number belongs to a special class of rare prime numbers known as Mersenne primes, named after a 17th century French monk who first studied them 350 years ago. So far only 42 have been found.

Yesterday Dr Nowak was reluctant to talk about his discovery, made using a special programme on his 2.4GHz Pentium 4 computer. "He's busy. He has a full afternoon seeing patients. He's doesn't want to comment," a spokeswoman at Dr Nowak's clinic said.

The eye surgeon is one of thousands of volunteers using software provided by the Great Internet Mersenne Prime Search (Gimps), a project to discover the holy grail of prime number research - a 10m-digit prime number. It took experts five days to work out that Dr Nowak's new number was indeed bigger than the previous biggest prime, discovered last May by an American. His number has 7,816,230 digits.

guardian.co.uk



To: exdaytrader76 who wrote (52)6/2/2006 8:21:00 AM
From: LPS5  Respond to of 79
 
Sorry so quiet lately.

I should add, with regard to the focus of the below article and my own personal undertakings in research and academia, much of the same can be said of the jumble of theorems, assertions and speculative articles touting what is generally referred to as "chaos theory."

*****

You Got Game Theory!
by Martin Kihn

It was all such fun until we realized that no business really uses game theory.

Game theory is the fun-sounding branch of economics introduced in the 1940s by Hungarian genius John von Neumann and developed in the 1950s by Princeton's John Nash, subject of the 2001 Oscar-winning film A Beautiful Mind.

Over the years, the status of game theory -- which describes the interactions of self-interested parties such as poker players and deal makers -- soared, and its insights were applied to fields as far-reaching as evolution, auctions, even counterterrorism. Playing along, we here at the CDU decided to find out just how much court time game theory gets in the big game of business. After all, it has been taught to almost every one of the some 2.5 million MBAs and economists in the United States alone. Surely, we thought, it would be a slam dunk to turn up dozens of examples of game theory applied in the real world.

Adopting our usual rigorous methodology, we set the following parameters. To count, an example must:

(1) be an actual business situation where somebody used the insights of game theory;

(2) have occurred within the past five years; and

(3) involve real, live, actual companies -- not governments, nonprofit organizations, or Russell Crowe.

First, we scoured the literature. We selected a relevant portfolio of 40 publications and submitted our queries. We tried again. And again. And we found...nothing. There were plenty of mentions of government spectrum auctions, and A Beautiful Mind came up hundreds of times. Not quite what we had in mind.

Perhaps, we thought, the media just doesn't get it. Undaunted, we assembled a panel of 30 respected game theorists around the world, and we sent them a survey asking, "Can you think of any examples of real, live companies that have consciously applied game-theoretical concepts to a real business problem?"

The response was...a deafening chorus of head scratching.

"The short answer is, I don't know," said David Levine of UCLA. "Let me think about this," replied MIT's Muhamet Yildiz.

Others on our expert panel, while not offering up any actual, you know, examples, were willing to speculate on why they couldn't.

Traditional game theory "prescribes a lot of advice that does not actually seem to work," admitted Paul Bartha of the University of British Columbia. Why not? Maybe because "the sorts of situations that would allow the application of formal methods are so simple that people can understand them without much help," suggested the University of Minnesota's Andy McLennan.

Does that mean game theory is just, um, common sense? "Game theory gives you a nice systematic way to think about strategy, but it's not magic," agreed Hal Varian, an economist at the University of California at Berkeley and coauthor of the bestselling Information Rules (Harvard Business School Press, 1999). Or, as MIT's David McAdams put it, "Game theory is really a frame of mind and, once you have it, you see it everywhere."

Everywhere, perhaps, and nowhere.

In the end, none of our experts had a concrete example. But many offered the same advice: "Ask Preston McAfee" -- an economist at the California Institute of Technology and perhaps the country's foremost working game theorist (he designed that government spectrum auction). He was more encouraging: "There are lots of examples," he emailed, agreeing to an interview.

We reached the professor in his office at Caltech. "So," we asked, "what are all these examples of game theory applied to real life?" There was a silence on the line. "Well," he said, "a lot of companies hired game theorists to prepare for those spectrum auctions." Okay - but what about nongovernment auction situations? "I don't know of any companies that employ pure game theorists -- but maybe they're keeping it quiet."

Very, very quiet.

Martin Kihn is author of House of Lies: How Management Consultants Steal Your Watch and Then Tell You the Time (Warner Books, March 2005).

pf.fastcompany.com