Theorems in geometry | Conjectures that have been proved

Dodecahedral conjecture

The dodecahedral conjecture in geometry is intimately related to sphere packing. László Fejes Tóth, a 20th-century Hungarian geometer, considered the Voronoi decomposition of any given packing of unit spheres. He conjectured in 1943 that the minimal volume of any cell in the resulting Voronoi decomposition was at least as large as the volume of a regular dodecahedron circumscribed to a unit sphere. Thomas Callister Hales and proved the conjecture in 1998, following the same strategy that led Hales to his proof of the Kepler conjecture. The proofs rely on extensive computations. McLaughlin was awarded the 1999 Morgan Prize for his contribution to this proof. (Wikipedia).

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How to Construct a Dodecahedron

How the greeks constructed the Dodecahedron. Euclids Elements Book 13, Proposition 17. In geometry, a dodecahedron is any polyhedron with twelve flat faces. The most familiar dodecahedron is the regular dodecahedron with regular pentagons as faces, which is a Platonic solid. A regular dode

From playlist Platonic Solids

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Canonical structures inside the Platonic solids III | Universal Hyperbolic Geometry 51

The dodecahedron is surely one of the truly great mathematical objects---revered by the ancient Greeks, Kepler, and many mathematicians since. Its symmetries are particularly rich, and in this video we look at how to see the five-fold and six-fold symmetries of this object via internal str

From playlist Universal Hyperbolic Geometry

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Area of dodecagon from a square!

This is a short, animated visual proof demonstrating that the area of a regular dodecagon inscribed in the unit circle has an area of exactly 3. #math​ #manim​ #visualproof​ #mathvideo​ #geometry #mathshorts​ #geometry #mtbos​ #animation​ #theorem​ #pww​ #proofwithoutwords​ #proof​ #it

From playlist MathShorts

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Dihedral group example

In this veideo we continue our look in to the dihedral groups, specifically, the dihedral group with six elements. We note that two of the permutation in the group are special in that they commute with all the other elements in the group. In the next video I'll show you that these two el

From playlist Abstract algebra

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Dodecahedron in Geogebra

Dodecahedron in Geogebra Step by step tutorial on this link: https://youtu.be/FPDOfPhheFk In case you wanna to pay me a drink: https://www.paypal.me/admirsuljicic/

From playlist Geogebra [Tutoriali]

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GraphData: New Developments and Research Applications

GraphData is an extensive curated database of simple graphs and their properties available in Mathematica as a built-in data paclet and in Wolfram|Alpha via natural language queries. GraphData was first introduced in Mathematica Version 6, and the number of graphs, property count, and frac

From playlist Wolfram Technology Conference 2013

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Combinatorics and Geometry to Arithmetic of Circle Packings - Nakamura

Speaker: Kei Nakamura (Rutgers) Title: Combinatorics and Geometry to Arithmetic of Circle Packings Abstract: The Koebe-Andreev-Thurston/Schramm theorem assigns a conformally rigid fi-nite circle packing to a convex polyhedron, and then successive inversions yield a conformally rigid infin

From playlist Mathematics

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Inside-Out Logic

A fold-up, slice-and-dice dodecahedron and its complement. With a 3D printer, you can make your own using the files here: http://georgehart.com/rp/T-O-M/t-o-m.html

From playlist Odds and Ends

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Dodecaplex: the puzzle from the fourth dimension!

Check out Dodecaplex on Maths Gear! https://mathsgear.co.uk/products/dodecaplex-puzzle Dodecaplex is based on the mathematics of Saul Schleimer and Henry Segerman. Henry Segerman http://www.segerman.org/ Saul Schleimer http://homepages.warwick.ac.uk/~masgar/ You can read more about the

From playlist Guest appearances

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The unexpected logic behind rolling multiple dice and picking the highest.

Check out Jane Street's icosahedron puzzle: https://www.janestreet.com/IMO2022/ 2022 International Mathematical Olympiad! https://www.imo2022.org/ If you want those d60 and d120 we sell them on Maths Gear or you can go direct to The Dice Lab. https://mathsgear.co.uk/collections/dice http

From playlist Prob and Stats

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Regular Dodecagon Surprises

Regular dodecagon surprises. How to prove? Source: Antonio Gutierrez. https://geogebra.org/m/wxywrnwh #GeoGebra #MTBoS #ITeachMath #geometry #math #maths #proof #ProofWithoutWords #EdTech #MathChat #GeomChat

From playlist Geometry: Challenge Problems

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30-Cell Puzzle

This shows a 3d print of a puzzle I produced using shapeways.com. This is joint work with Saul Schleimer. This is available at http://shpws.me/lmxi. A larger version of the puzzle is available at http://shpws.me/lmxi.

From playlist 3D printing

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Dodecahedral holonomy maze

Available from Shapeways: https://www.shapeways.com/shops/henryseg?section=Holonomy+mazes Thanks to Sabetta Matsumoto and Chaim Goodman-Strauss for building the sculpture, to Saul Schleimer for naming the "rook", and to all of them for helpful conversations.

From playlist 3D printing

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How do ceramic crystal structures differ from metal crystal structures?

Metal crystal structures are much simpler than ceramic structures. This is due to two reasons. First, ceramics have positive and negative charged ions. Cations and ions must maintain charge neutrality. Second, the size of cations and anions are very different! Structures with multiple diff

From playlist Materials Sciences 101 - Introduction to Materials Science & Engineering 2020

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To Build Viruses: A Markov Chain Monte Carlo Algorithm for Stimulating Viral Assembly Kinetics

For the latest information, please visit: http://www.wolfram.com Speaker: Nicholas Brunk Wolfram developers and colleagues discussed the latest in innovative technologies for cloud computing, interactive deployment, mobile devices, and more.

From playlist Wolfram Technology Conference 2015

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Ian Agol, Lecture 3: Applications of Kleinian Groups to 3-Manifold Topology

24th Workshop in Geometric Topology, Calvin College, June 30, 2007

From playlist Ian Agol: 24th Workshop in Geometric Topology

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Bridges 2014 talk: The quaternion group as a symmetry group

This is a talk I gave at the Bridges conference on mathematics and the arts (http://bridgesmathart.org/), on 18th August 2014, about my paper with Vi Hart with the same title. The slides are available at https://www.math.okstate.edu/~segerman/talks/quaternion_group_as_a_symmetry_group.pdf

From playlist 3D printing

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Dodecahedron of Demolition

Demolition with dodecahedrons of various masses, trajectories, and velocities.

From playlist Physics

Related pages

Geometry | Sphere packing | Regular dodecahedron | László Fejes Tóth | Unit sphere | Kepler conjecture