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 Jirka
 AviFest, AviStories and Amazing Cash Prizes.
 Polymath 10 post 6: The ErdosRado sunflower conjecture, and the Turan (4,3) problem: homological approaches.
 Polymath 10 Emergency Post 5: The ErdosSzemeredi Sunflower Conjecture is Now Proven.
 Mind Boggling: Following the work of Croot, Lev, and Pach, Jordan Ellenberg settled the cap set problem!
 More Math from Facebook
 The Erdős Szekeres polygon problem – Solved asymptotically by Andrew Suk.
 The Quantum Computer Puzzle @ Notices of the AMS
 Three Conferences: Joel Spencer, April 2930, Courant; Joel Hass May 2022, Berkeley, Jean Bourgain May 2124, IAS, Princeton
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 The Erdős Szekeres polygon problem  Solved asymptotically by Andrew Suk.
 A Breakthrough by Maryna Viazovska Leading to the Long Awaited Solutions for the Densest Packing Problem in Dimensions 8 and 24
 Jirka
 Believing that the Earth is Round When it Matters
 Amazing: Peter Keevash Constructed General Steiner Systems and Designs
 Greg Kuperberg: It is in NP to Tell if a Knot is Knotted! (under GRH!)
 Polymath 10 Emergency Post 5: The ErdosSzemeredi Sunflower Conjecture is Now Proven.
 When It Rains It Pours
 Extremal Combinatorics III: Some Basic Theorems
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Category Archives: Test your intuition
TYI 26: Attaining the Maximum
(Thanks, Dani!) Given a random sequence , ******, , let . and assume that . What is the probability that the maximum value of is attained only for a single value of ? Test your intuition: is this probability bounded … Continue reading
TYI 25: The Automorphism Group of the Symmetric Group
True or False: The group of automorphisms of the symmetric group , n ≥ 3 is itself.
Posted in Algebra and Number Theory, Test your intuition
Tagged Test your intuition, the symmetric group
7 Comments
Test your intuition 24: Which of the following three groups is trivial
Martin Bridson We have three finitely presented groups A is generated by two generators a and b and one relation B is generated by three generators a, b, c and three relations , . C is generated by four generators a, b, c, d … Continue reading
Posted in Algebra and Number Theory, Test your intuition
Tagged Martin Bridson, Test your intuition
10 Comments
Test Your Intuition (23): How Many Women?
How many women can you find on this poster announcing the 25th Jerusalem School in Economics Theory devoted to Matching and Market Design? Please respond to the poll:
Answer to Test Your Intuition (22)
Indeed, most people got it right! Bundling sometimes increases revenues, sometimes keeps revenues the same, and sometimes decreases revenues. In fact, this is an interesting issue which was the subject of recent research effort. So here are a few … Continue reading
Posted in Economics, Test your intuition
Tagged Auctions, Noam Nisan, Sergiu Hart, Test your intuition
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Test your intuition (22): Selling Two Items in a Bundle.
One item You have one item to sell and you need to post a price for it. There is a single potential buyer and the value of the item for the buyer is distributed according to a known probability distribution. It … Continue reading
Auctionbased Tic Tac Toe: Solution
Reshef, Moshe and Sam The question: (based on discussions with Reshef Meir, Moshe Tennenholtz, and Sam Payne) Tic Tac Toe is played since anciant times. For the common version, where the two players X and O take turns in marking … Continue reading
Test Your Intuition (21): Auctions
You run a singleitem sealed bid auction where you sell an old camera. There are three bidders and the value of the camera for each of them is described by a certain (known) random variable: With probability 0.9 the value … Continue reading
Posted in Economics, Games, Test your intuition
Tagged Auctions, Roger Myerson, Test your intuition
4 Comments
Oz’ Balls Problem: The Solution
A commentator named Oz proposed the following question: You have a box with n red balls and n blue balls. You take out each time a ball at random but, if the ball was red, you put it back in the box and take out … Continue reading
Posted in Probability, Test your intuition
Tagged Erosion, J. F. C. Kingman, Probability, S. E. Volkov
1 Comment
Answer: Lord Kelvin, The Age of the Earth, and the Age of the Sun
Yeshu Kolodni and Lord Kelvin The question In 1862, the physicist William Thomson (who later became Lord Kelvin) of Glasgow published calculations that fixed the age of Earth at between 20 million and 400 … Continue reading
Posted in Geology, Physics, Test your intuition
4 Comments