# Monthly Archives: February 2010

## Test Your Intuition (11): Is it Rational to Insure a Toaster

Here is a question from last year’s exam in the course “Basic Ideas of Mathematics”:   You buy a toaster for 200 NIS (\$50) and you are offered one year of insurance for 24 NIS (\$6).   a) Is it … Continue reading

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## The Beauty of Mathematics

This semester I am teaching an introductory course in mathematics for students in other departments.  I taught a similar course last year entitled “Basic Ideas in Mathematics,” and this year, following a suggestion of my wife, I changed the name to “The Beauty of Mathematics”. Another … Continue reading

Posted in Teaching | 26 Comments

## Nerves of Convex Sets – A Recent Result by Martin Tancer

Martin Tancer recently found a very beautiful proof that finite projective planes can’t be represented by convex sets in any fixed dimension. This was asked in the paper entitled “Transversal numbers for hypergraphs arising in geometry” by Noga Alon, Gil … Continue reading

Posted in Convexity | 2 Comments

## Itamar Pitowsky: Probability in Physics, Where does it Come From?

I came across a videotaped lecture by Itamar Pitowsky given at PITP some years ago on the question of probability in physics that we discussed in two earlier posts on randomness in nature (I, II). There are links below to … Continue reading

Posted in Obituary, Philosophy, Physics, Probability | | 1 Comment

## Noise Stability and Threshold Circuits

The purpose of this post is to describe an old conjecture (or guesses, see this post) by Itai Benjamini, Oded Schramm and myself (taken from this paper) on noise stability of threshold functions. I will start by formulating the conjectures and … Continue reading

## The Möbius Undershirt

“Look at this brand new undershirt,” my wife said. “I am shaking it and shaking it but still I have this twist.  Can you see what to do?”  I gave the undershirt a good shake. And another one. And one more. And … Continue reading

## Anat Lotan: Who is Gina II, My Own Shocking Revelation

Who’s Gina? (Part 2): My Own Shocking Revelation By: Anat Lotan It was one of those typically hot Israeli end-of-August days; a scorching summer morning, where you have to convince yourself that the cool breezes of autumn are just around … Continue reading

Posted in Gina Says, Guest blogger | Tagged , | 4 Comments

## Anat Lotan: Who is Gina I

Several people asked me to explain who is Gina, the hero of my book “Gina says:  Adventures in the Blogosphere String War.” There was a chapter written by Anat Lotan about who Gina is.  And in view of the … Continue reading

Posted in Gina Says | Tagged , | 1 Comment

## A Discrepancy Problem for Planar Configurations

Yaacov Kupitz and Micha A. Perles asked: What is the smallest number C such that for every configuration of n points in the plane there is a line containing two or more points from the configuration for which the difference between the … Continue reading

Posted in Combinatorics | | Leave a comment

## The Ultimate Riddle

Click on the picture!

Posted in Riddles | Tagged | 15 Comments