# Monthly Archives: June 2009

This is not as clear cut a question as the earlier ones, and if you do not know an answer then it will be difficult to figure one out just based on intuition. (But perhaps possible). If you are intrigued by … Continue reading

## Praise For ‘Gina says’

Praise for: ” ‘Gina Says,’ Adventures in the Blogsphere String War (Below the dividing line:  Greg Kuperberg, Scott Aaronson, Clifford Johnson, Peter Woit, Motty Perry, Caterina Calsamiglia, Yuval Peres, Eva Illouz, and (right from the comment section)  Luca Trevisan, Thomas … Continue reading

Posted in Book review, Gina Says | 11 Comments

## My Book: “Gina Says,” Adventures in the Blogosphere String War

I wrote a book. It is a sort of a popular science book and it is also about blogging and debating. You can download the first part of the book : It is a 94 page pdf file.     “Gina Says,” Adventures in … Continue reading

Posted in Blogging, Gina Says | 35 Comments

## A Little Story Regarding Borsuk’s Conjecture

Jeff Kahn Jeff and I worked on the problem for several years. Once he visited me with his family for two weeks. Before the visit I emailed him and asked: What should we work on in your visit? Jeff asnwered: … Continue reading

Posted in Uncategorized | Tagged | 7 Comments

## Borsuk’s Conjecture

Karol Borsuk conjectured in 1933 that every bounded set in can be covered by sets of smaller diameter.  Jeff Kahn and I found a counterexample in 1993. It is based on the Frankl-Wilson theorem. Let be the set of vectors of length . … Continue reading

Posted in Combinatorics | Tagged , | 6 Comments

## Istanbul!

Posted in Uncategorized | 6 Comments

## Banknotes with Pictures of Mathematicians

Are you aware of any? (current ones? old ones?)

Posted in Uncategorized | 12 Comments

(Not such a set) consider a planar set A with the following property. In every direction, the distance between the two parallel lines that touch A from both sides is the same! Must A be a circle?