Lớp 9 năm học 2022-2023: Một số đề luyện tập

Trong bài này tôi sẽ giới thiệu một số đề luyện tập cho học sinh lớp 9 năm học 2022-2023.

Học sinh lớp 8 có thể làm được cả 4 bài trong đề này.

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Alexander A. Gaifullin: Many 27-vertex Triangulations of Manifolds Like the Octonionic Projective Plane (Not Even One Was Known Before). August 19, 2022

From top left clockwise: Alexander Gaifullin, Denis Gorodkov, Ulrich Brehm, Wolfgang Kühnel Here is the paper: Alexander A. Gaifullin: 634 vertex-transitive and more than 10¹⁰³ non-vertex-transitive 27-vertex triangulations of manifolds like the octonionic projective plane Abstract with annotation: In … Continue reading →

Gil Kalai

Answer to Test Your Intuition 50: Detecting a Deviator August 15, 2022

Two weeks ago we asked: Ruth and Ron start together at the origin and take a walk on the integers. Every day they make a move. They take turns in flipping a coin and they move together right or left … Continue reading →

Gil Kalai

To cheer you up in difficult times 36: The Immense Joy of Fake Reverse Parking August 11, 2022

Fake reverse parking Update: fake reverse parking is known already as the much debated “pull-through parking”. (Thanks to Gali Weinstein over Facebook for telling me about it.) It is also mentioned as #879 among a thousand awesome things by Neil … Continue reading →

Gil Kalai

Ordinary computers can beat Google’s quantum computer after all August 6, 2022

Science magazine has an article written by Adrian Cho Ordinary computers can beat Google’s quantum computer after all. It is about the remarkable progress in classical simulations of sampling task like those sampling tasks that led to the 2019 Google’s … Continue reading →

Gil Kalai

Test Your Intuition 50. Two-Player Random Walk; Can You Detect Who Did Not Follow the Rules? August 3, 2022

Ruth and Ron start together at the origin and take a walk on the integers. Every day they make a move. They take turns in flipping a coin and they move together right or left according to the outcome. Their … Continue reading →

Gil Kalai

ICM 2022. Kevin Buzzard: The Rise of Formalism in Mathematics July 17, 2022

In this post I would like to report on Kevin Buzzard’s spectacular lecture on moving mathematics toward formal mathematical proofs. (Here are the slides.) The picture above is based on images from the other spectacular Saturday morning lecture by Laure … Continue reading →

Gil Kalai

ICM 2022: Langlands Day July 13, 2022

ICM 2022 is running virtually and you can already watch all the videos of past lectures at the IMU You-Tube channel, and probably even if you are not among the 7,000 registered participants you can see them “live” on You-Tube … Continue reading →

Gil Kalai

ICM 2022 awarding ceremonies (1) July 6, 2022

Hugo Duminil-Copin, June Huh, James Maynard and Maryna Viazovska were awarded the Fields Medal 2022 and Mark Braverman was awarded the Abacus Medal 2022. I am writing from Helsinki where I attended the meeting of the General Assembly of the … Continue reading →

Gil Kalai

ICM 2022 Virtual Program, Live events, and Dynamics Week in Jerusalem June 30, 2022

ICM 2022 Next Tuesday, July 5 2022 will be the opening day of the International Congress of Mathematicians (ICM 2022) that, because of the war in Ukraine, will be fully virtual. Here is the link for the program for ICM … Continue reading →

Gil Kalai

Algorithmic Game Theory: Past, Present, and Future June 26, 2022

Noam Nisan is 60 Today, June 26 2022, is the opening day of Algorithmic Game Theory: Past, Present, and Future, a workshop in honor of Noam Nisan’s 60th Birthday. The workshop takes place on June 26-30 2022, at the CS … Continue reading →

Gil Kalai

Terence Tao

What are the odds? October 4, 2022

An unusual lottery result made the news recently: on October 1, 2022, the PCSO Grand Lotto in the Philippines, which draws six numbers from to at random, managed to draw the numbers (though the balls were actually drawn in the order ). In other words, they drew exactly six multiples of nine from to . […]

Terence Tao

A counterexample to the periodic tiling conjecture September 20, 2022

Rachel Greenfeld and I have just uploaded to the arXiv our announcement “A counterexample to the periodic tiling conjecture“. This is an announcement of a longer paper that we are currently in the process of writing up (and hope to release in a few weeks), in which we disprove the periodic tiling conjecture of Grünbaum-Shephard […]

Terence Tao

Using the Smith normal form to manipulate lattice subgroups and closed torus subgroups July 20, 2022

Let denote the space of matrices with integer entries, and let be the group of invertible matrices with integer entries. The Smith normal form takes an arbitrary matrix and factorises it as , where , , and is a rectangular diagonal matrix, by which we mean that the principal minor is diagonal, with all other […]

Terence Tao

Request for comments from the ICM Structure Committee July 17, 2022

[This post is collectively authored by the ICM structure committee, whom I am currently chairing – T.] The ICM structure committee is responsible for the preparation of the Scientific Program of the International Congress of Mathematicians (ICM). It decides the structure of the Scientific Program, in particular, the number of plenary lectures, the sections a […]

Terence Tao

ICM and IMU award ceremony begins tomorrow July 4, 2022

I’m currently in Helsinki, Finland for the General Assembly meeting of the International Mathematical Union (IMU), which runs the International Congress of Mathematicians (ICM) as well as several other events and initiatives. In particular the assembly voted on the location of the 2026 ICM; it will be held in Philadelphia, USA (with the general assembly […] […]

Terence Tao

Registration for the virtual ICM is now open June 2, 2022

The (now virtual) 2022 International Congress of Mathematicians, which will be held on July 6-14, now has open registration (free of charge). I’ll also take this opportunity to mention that there are a large number of supporting satellite events for the virtual ICM, which are listed on this web page. I’d like to draw particular […]

Terence Tao

Notes on inverse theorem entropy May 27, 2022

Let be a finite set of order ; in applications will be typically something like a finite abelian group, such as the cyclic group . Let us define a -bounded function to be a function such that for all . There are many seminorms of interest that one places on functions that are bounded by […]

Terence Tao

Partially specified mathematical objects, ambient parameters, and asymptotic notation May 11, 2022

In orthodox first-order logic, variables and expressions are only allowed to take one value at a time; a variable , for instance, is not allowed to equal and simultaneously. We will call such variables completely specified. If one really wants to deal with multiple values of objects simultaneously, one is encouraged to use the language […]

Terence Tao

Higher uniformity of arithmetic functions in short intervals I. All intervals April 11, 2022

Kaisa Matomäki, Xuancheng Shao, Joni Teräväinen, and myself have just uploaded to the arXiv our preprint “Higher uniformity of arithmetic functions in short intervals I. All intervals“. This paper investigates the higher order (Gowers) uniformity of standard arithmetic functions in analytic number theory (and specifically, the Möbius function , the von Mango […]

Terence Tao

Nominations for 2023 Doob prize now open April 7, 2022

Just a brief announcement that the AMS is now accepting (until June 30) nominations for the 2023 Joseph L. Doob Prize, which recognizes a single, relatively recent, outstanding research book that makes a seminal contribution to the research literature, reflects the highest standards of research exposition, and promises to have a deep and long-term impact in […]

Terence Tao

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