Author Archives: Gil Kalai

If Quantum Computers are not Possible Why are Classical Computers Possible?

As most of my readers know, I regard quantum computing as unrealistic. You can read more about it in my Notices AMS paper and its extended version (see also this post) and in the discussion of Puzzle 4 from my … Continue reading

Posted in Computer Science and Optimization, Physics, Quantum | Tagged , | Leave a comment

Sergiu Hart: Two-Vote or not to Vote

  Sergiu Hart raises a very interesting idea regarding elections. Consider the Brexit referendum. Sergiu  proposes to have two rounds two weeks apart.  Every voter can vote in each, and the votes of both rounds add up! The outcomes of … Continue reading

Posted in Economics, Games | Tagged , | 13 Comments

A toast to Alistair: Two Minutes on Two Great Professional Surprises

Alistair and the Simons Institure friendly and helpful staff  Luca Trevisan invited me to give a 3-minute (vidotaped or live) toast for Alistair Sinclair to celebrate that Alistair much deservedly received the SIGACT service award and to mourn that he also … Continue reading

Posted in Computer Science and Optimization, Updates | Tagged | Leave a comment

TYI 31 – Rados Radoicic’s Rope Problem

  Ropemaker (source) Rados Radoicic wrote me: “Several years back, I heard the following puzzle that turns out to be rather ‘classical’: “There are N ropes in a bag. In each step, two rope ends are picked uniformly at random, tied … Continue reading

Posted in Combinatorics, Probability, Test your intuition | Tagged , | 7 Comments

Eran Nevo: g-conjecture part 4, Generalizations and Special Cases

This is the fourth in a series of posts by Eran Nevo on the g-conjecture. Eran’s first post was devoted to the combinatorics of the g-conjecture and was followed by a further post by me on the origin of the g-conjecture. Eran’s second post was about … Continue reading

Posted in Combinatorics, Convex polytopes, Guest blogger, Open problems | Tagged , | 2 Comments

The World of Michael Burt: When Architecture, Mathematics, and Art meet.

  This remarkable 3D geometric object tiles space! It is related to a theory of “spacial networks” extensively studied by Michael Burt and a few of his students. The network associated to this object is described in the picture below. … Continue reading

Posted in Art, Combinatorics, Geometry | Tagged , , | 4 Comments

Layish

This story is implicitly referred to in the 2008 opening post of this blog. ———– It was high time to raise the level of the discussion, I thought. Princeton, Fall 1995. We were a group of mathematicians at the IAS … Continue reading

Posted in Combinatorics, Computer Science and Optimization, Games, Mathematics to the rescue, Philosophy, Rationality, Sport, Taxi-and-other-stories | Tagged , , | 4 Comments

Some Mathematical Puzzles that I encountered during my career

Recently, I gave some lectures based on a general-audience personal tour across four (plus one) mathematical puzzles that I encountered during my career. Here is a paper based on these lectures which is meant for a very wide audience (in … Continue reading

Posted in Combinatorics, Computer Science and Optimization, Quantum | Tagged | 1 Comment

Friendship and Sesame, Maryam and Marina, Israel and Iran

Happy new (Jewish) year everybody. Amazing scientific partnership  between Jordan, Cyprus, Egypt, Iran, Israel, Pakistan, the Palestinian Authority, and Turkey SESAME (Synchrotron-light for Experimental Science and Applications in the Middle East) is a “third-generation” synchrotron light source that was officially opened in Allan (Jordan) on 16 May 2017. … Continue reading

Posted in Obituary, Updates, Women in science | Tagged , , , , | 1 Comment

Elchanan Mossel’s Amazing Dice Paradox (your answers to TYI 30)

TYI 30 asked Elchanan Mossel’s Amazing Dice Paradox (that I heard from Yuval Peres yesterday) You throw a die until you get 6. What is the expected number of throws (including the throw giving 6) conditioned on the event that all throws … Continue reading

Posted in Combinatorics, Probability, Test your intuition | Tagged , | 62 Comments