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# Monthly Archives: November 2008

## Sarkaria’s Proof of Tverberg’s Theorem 2

Karanbir Sarkaria 4. Sarkaria’s proof: Tverberg’s theorem (1965): Let be points in , . Then there is a partition of such that . Proof: We can assume that . First suppose that the points belong to the -dimensional affine space … Continue reading

## Sarkaria’s Proof of Tverberg’s Theorem 1

Helge Tverberg Ladies and gentlemen, this is an excellent time to tell you about the beautiful theorem of Tverberg and the startling proof of Sarkaria to Tverberg’s theorem (two parts). A good place to start is Radon’s theorem. 1. The theorems of Radon, … Continue reading

## Bad Advice; An Answer to an Old Trivia Question

A transparency and a lecture using transparencies. (No relation to the advice.) Our bad, worse and worst advice corner Bad – When you give a talk with transparencies or computer presentations, don’t go over the content of the transparencies but rather assume … Continue reading

## Thomas Bayes and Probability

How can we assign probabilities in cases of uncertainty? And what is the nature of probabilities, to start with? And what is the rational mechanism for making a choice under uncertainty? Thomas Bayes lived in the eighteenth century. Bayes’ famous … Continue reading

## About Conjectures: Shmuel Weinberger

The following paragraph is taken from the original “too personal for publication draft” of an article entitled ” ‘Final values’ of functors” by Shmuel Weinberger for a volume in honor of Guido Mislin’s retirement from ETH. (L’enseignement Mathematique 54(2008), 180-182.) Shmuel’s remarks … Continue reading

## Would you decide the election if you could?

One mental experiment I am fond of asking people (usually before elections) is this: Suppose that just a minute before the votes are counted you can change the outcome of the election (say, the identity of the winner, or even … Continue reading

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## Impagliazzo’s Multiverse

Update (July 2009): Here are links to a related post on Lipton’s blog, and a conference announcement on Russell’s possible worlds. On the occasion of Luca’s post on his FOCS 2008 tutorial on average-case complexity here is a reminder of Russell … Continue reading

## Detrimental Noise

“Imagine there’s no heaven, it’s easy(?) if you try,” John Lennon Disclaimer: It is a reasonable belief (look here, and here), and an extremely reasonable working assumption (look here) that computationally superior quantum computers can be built. (This post and the … Continue reading