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 Open problem session of HUJICOMBSEM: Problem #1, Nati Linial – Turan type theorems for simplicial complexes.
 Péter Pál Pach and Richárd Palincza: a Glimpse Beyond the Horizon
 To cheer you up 14: Hong Liu and Richard Montgomery solved the Erdős and Hajnal’s odd cycle problem
 To cheer you up in difficult times 13: Triangulating real projective spaces with subexponentially many vertices
 Benjamini and Mossel’s 2000 Account: Sensitivity of Voting Schemes to Mistakes and Manipulations
 Test Your Intuition (46): What is the Reason for Maine’s Huge Influence?
 This question from Tim Gowers will certainly cheeer you up! and test your intuition as well!
 Three games to cheer you up.
 Cheerful Test Your Intuition (#45): Survey About Sisters and Brothers
Top Posts & Pages
 Open problem session of HUJICOMBSEM: Problem #1, Nati Linial  Turan type theorems for simplicial complexes.
 Péter Pál Pach and Richárd Palincza: a Glimpse Beyond the Horizon
 To cheer you up 14: Hong Liu and Richard Montgomery solved the Erdős and Hajnal's odd cycle problem
 TYI 30: Expected number of Dice throws
 Elchanan Mossel's Amazing Dice Paradox (your answers to TYI 30)
 This question from Tim Gowers will certainly cheeer you up! and test your intuition as well!
 Cheerful Test Your Intuition (#45): Survey About Sisters and Brothers
 Answer: Lord Kelvin, The Age of the Earth, and the Age of the Sun
 To cheer you up in difficult times 13: Triangulating real projective spaces with subexponentially many vertices
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Monthly Archives: April 2018
Testing *My* Intuition (34): Tiling High Dimension with an Arbitrary LowDimensional Tile.
Test your intuition 34 asked the following: A tile is a finite subset of . We can ask if can or cannot be partitioned into copies of . If can be partitioned into copies of we say that tiles . Here … Continue reading
Posted in Combinatorics, Test your intuition
Tagged Adam Chalcraft, Imre Leader, Ta Sheng Tan, Vytautas Gruslys
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My Copy of Branko Grünbaum’s Convex Polytopes
Branko Grünbaum is my academic grandfather (see this highly entertaining post for a picture representing five academic generations). Gunter Ziegler just wrote a beautiful article in the Notices of the AMS on Branko Grunbaum’s classic book “Convex Polytopes”, so this … Continue reading
Posted in Combinatorics, Convex polytopes, People
Tagged Branko Grunbaum, Dom de Caen, Günter Ziegler
4 Comments
Cohen, Haeupler, and Schulman: Explicit Binary TreeCodes & Cancellations
The highdimensional conference in Jerusalem is running with many exciting talks (and they are videotaped), and today in Tel Aviv there is a conference on Optimization and Discrete Geometry : Theory and Practice. Today in Jerusalem, Leonard Schulman talked (video available!) … Continue reading
Test Your Intuition (34): Tiling high dimensional spaces with twodimensional tiles.
A tile is a finite subset of . We can ask if can or cannot be partitioned into copies of . If can be partitioned into copies of we say that tiles . Here is a simpe example. Let consists of … Continue reading
Coloring Problems for Arrangements of Circles (and Pseudocircles)
To supplement and celebrate Aubrey de Grey’s result here are Eight problems on coloring circles A) Consider a finite family of unit circles. What is the minimum number of colors needed to color the circles so that tangent circles are … Continue reading
Posted in Combinatorics, Geometry, Open problems
Tagged Geometric combinatorics, geometric graphs, Graphcoloring
12 Comments
Aubrey de Grey: The chromatic number of the plane is at least 5
A major progress on an old standing beautiful problem. Aubrey de Grey proved that the chromatic number of the plane is at least 5. (I first heard about it from Alon Amit.) The Hadwiger–Nelson problem asks for the minimum number of … Continue reading
Posted in Combinatorics, Geometry, Open problems, Updates
Tagged Aubrey de Grey, The Hadwiger–Nelson problem
11 Comments
Conference on High Dimensional Combinatorics, April 2226 2018
Conference on High Dimensional Combinatorics Conference homepage Dates: April 2226, 2018 Place: Israel Institute for Advanced Studies, The Hebrew University of Jerusalem Organizers: Alex Lubotzky, Tali Kaufman and Oren Becker Registration form: click here Registration deadline: April 13, 2018 Combinatorics in general and the theory … Continue reading
Nathan Rubin Improved the Bound for Planar Weak εNets and Other News From EinGedi
I just came back from a splendid visit to Singapore and Vietnam and I will write about it later. While I was away, Nathan Rubin organized a lovely conference on topics closed to my heart ERC Workshop: Geometric Transversals and EpsilonNets with … Continue reading