Moshe Vardi wrote a short interesting essay “What is theoretical computer science?” (It followed by interesting posts on Facebook.) Moshe argues that Thinking of theoretical computer science (TCS) as a branch of mathematics is harmful to the discipline. I personally … Continue reading →
“Time for Peace” (זמן לשלום), Lyrics: Amnon Abutbul, Yair Dalal, Fathi Kasem; Melody: Amnon Abutbul. Performing Shlomit Aharon and Yevgeni Shapovalov. This year I had the rare event that the new Jewish year coincides with my birthday, and “time for … Continue reading →
There are very many irrational numbers but proving irrationality of a specific number is not a common event. A few weeks ago Frank Calegari, Vesselin Dimitrov, and Yunqing Tang posted a paper that proved the irrationality of . In fact … Continue reading →
Viterbo conjecture – refuted Claude Viterbo’s 2000 volume-capacity conjecture asserts that the Euclidean (even dimensional) ball maximizes (every) symplectic capacity among convex bodies of the same volume. In the recent paper A Counterexample to Viterbo’s Conjecture, Pazit Haim-Kislev and Yaron … Continue reading →
TYI56 asked the following question of Timothy Chow: You have fifteen boxes labelled with the English letters from A to O. Two identical prizes are placed in two (distinct) boxes chosen at random. Andrew’s search order is ABCDEFGHIJKLMNO. Barbara’s search … Continue reading →
To me and to many mathematicians in Israel, the Annual meeting of the Israeli Mathematical Union is a dear event and we try to take part. (Here we briefly described the 2017 meeting in Acre, and here the 2014 meeting … Continue reading →
Israeli Mathematical Union annual meeting and student talks day, Sunday and Monday, September 8 – 9, 2024. The Annual meeting of the Israeli Mathematical Union will be held on Sunday, September 8th 2024 at the Weizmann Institute. The main speakers … Continue reading →
Andrew and Barbara are playing a game. Fifteen boxes are arranged in a 3-by-5 grid, labeled with the letters A through O, as shown below. A B C D E F G H I J K L M N O … Continue reading →
“Quantum supremacy is important both in its own right and as a benchmark or step toward something further. But my theory is that quantum supremacy cannot be achieved, and this is based on analysis of the stochastic behavior of samples … Continue reading →
Here is a great question invented by Michele Piccione and Ariel Rubinstein. (Let me use this opportunity to recommend their mind boggling 1997 paper on the absent-minded driver.) The question (TYI 55) The proportion of newborns with a specific genetic … Continue reading →
I will report on Christian Elsholtz, Zach Hunter, Laura Proske, Lisa Sauermann’s breakthrough paper Sets without arithmetic progressions in integers and over finite fields. The paper improves Behrend’s 1946 construction for 3-AP free sets of integers. An important aspect of … Continue reading →
This post was kindly contributed by Ron Aharoni. Following Ron’s 2009 (Hebrew) book on philosophy החתול שאיננו שם the two of us had in 2010 a long discussion on various philosophical questions with emphasis on the free will problem. Ron … Continue reading →
Jiří Matoušek was a great mathematician and computer scientist and a wonderful person who enlightened our communities and our lives in many ways. A few weeks ago I visited beautiful Prague (and the historic building of the computer science and … Continue reading →
Congratulations to Noga Alon and Adi Shamir for winning the 2024 Wolf Prize. Noga Alon received the prize “for his fundamental contributions to Combinatorics and Theoretical Computer Science,” and Adi Shamir “for his fundamental contributions to Mathematical Cryptography.” This is … Continue reading →
I would like to discuss the following remarkable paper posted on the arXiv in June 2023. Effect of Non-unital Noise on Random Circuit Sampling, by Bill Fefferman, Soumik Ghosh, Michael Gullans, Kohdai Kuroiwa, and Kunal Sharma’s Abstract: In this work, … Continue reading →
Andrew Granville (home page; the comics book: “The Prime Suspects“) Andrew Granville, a famous number theorist, wrote a wonderful paper about proofs in mathematics published at the Annals of Mathematics and Philosophy. M×Φ Accepted Proofs: Objective Truth, or Culturally Robust? … Continue reading →
From left to right: Andrii Arman, Andriy Bondarenko and Danylo Radchenko, Fedor Nazarov, and Andriy Primak. The -dimensional unit Euclidean ball has width 2 in every direction. Namely, when you consider a pair of parallel tangent hyperplanes in any direction … Continue reading →
Let me share an announcement of a zoom lecture by Sheila Sundaram. The lecture (tomorrow, Sunday) is about the paper Koszulity, supersolvability, and Stirling representations, by Ayah Almousa, Victor Reiner, and Sheila Sundaram. _____________ Bar-Ilan Combinatorics Seminar The next meeting … Continue reading →
My new (and first!) paper with Dr. Z. Gil Kalai and Doron Zeilberger, Bijective and Automated Approaches to Abel Sums Abstract: In this tribute to our guru, Dominique Foata, we return to one of our (and Foata’s) first loves, and … Continue reading →
The first part of the post is devoted to eight-year anniversary of my 2016 paper. I will go on to describe a recent lecture by Dorit Aharonov and conclude with my toast to Michael Ben-Or. The Quantum Computer Puzzle, Notices … Continue reading →
Happy Passover to all our readers On the way from Cambridge to Tel Aviv I had a splendid three hour visit to London (from Kings Cross to UCL and back), where I met my graduate student Gabriel Gendler and Freddie … Continue reading →
I am writing from Cambridge, UK, where I participated in an impressive conference celebrating Tim Gowers’s 60 birthday and I an about to take part in a satellite workshop of Theoretical computer science. Coming here was my first travel since … Continue reading →
Our new paper Yosi Rinott, Tomer Shoham and I wrote a new paper on our statistical study of the data from the 2019 Google quantum supremacy experiment. Random Circuit Sampling: Fourier Expansion and Statistics, by Gil Kalai, Yosef Rinott, and … Continue reading →
Jerusalem October 4, 2023 The picture on the right is from ~ 60 years ago. Tel Aviv, five sunsets and a horse Efi Arazi school of Computer Science Corona times Tel Aviv (in the balcony – our grandchildren) with my … Continue reading →
A carpet of flowers in Shokeda, near Gaza, a few years ago. This is the fourth post of this type (I (2008); II(2011); III(2015).) I started planning this post in 2019 but as it turned out, earlier drafts have quickly … Continue reading →
In the picture (compare it to this picture in this post) you can see David DiVincenzo’s famous 7-steps road map (from 2000) to quantum computers, with one additional step “quantum supremacy on NISQ computers” that has proposed around 2010. Step … Continue reading →
Two weeks ago, I participated (remotely) in the discrete geometry Oberwolfach meeting, and Ramon van Handel gave a beautiful lecture about the equality cases of Alexandrov-Fenchel inequalities which is among the most famous problems in convex geometry. In the top … Continue reading →
Alex Samorodnitsky The most powerful general method for proving upper bounds for the size of error correcting codes and of spherical codes (and sphere packing) is the linear programming method that goes back to Philippe Delsarte. There are very interesting … Continue reading →
The following question was inspired by recent comments to the post on Elchanan Mossel’s amazing Dice Paradox. A fair dice is a dice that when thrown you get each of the six possibilities with probability 1/6. A random dice is … Continue reading →
Two months ago I presented five riddles and here, in this post, you will find a few more. (These types of riddles are called by Maya Bar-Hillel “stumpers”.) This time, we will have a discussion about how riddles are related … Continue reading →
Today, I want to tell you a little about the following paper that solves a conjecture of Laszlo Lovász and Yechiam Yemini from 1982 and an even stronger conjecture of Bob Connelly, Tibor Jordán, and Walter Whiteley from 2013: Every … Continue reading →
Fun with Algorithms FUN is a series of conferences dedicated to the use, design, and analysis of algorithms and data structures, focusing on results that are “fun” but also original and scientifically solid. “Fun” can be defined in many ways: … Continue reading →
A few days ago, a new striking paper appeared on the arXiv A new lower bound for sphere packing by Marcelo Campos, Matthew Jenssen, Marcus Michelen, and Julian Sahasrabudhe Here is the abstract: We show there exists a packing of … Continue reading →
The main purpose of this post is to tell you about a recent paper by Dan Romik which gives a direct proof of two crucial inequalities in Maryna Viazovska’s proof that lattice sphere packing is the densest sphere packing in … Continue reading →