Disproved conjectures | Algebraic topology
Ganea's conjecture is a claim in algebraic topology, now disproved. It states that for all , where is the Lusternik–Schnirelmann category of a topological space X, and Sn is the n-dimensional sphere. The inequality holds for any pair of spaces, and . Furthermore, , for any sphere , . Thus, the conjecture amounts to . The conjecture was formulated by Tudor Ganea in 1971. Many particular cases of this conjecture were proved, till finally Norio Iwase gave a counterexample in 1998. In a follow-up paper from 2002, Iwase gave an even stronger counterexample, with X a closed, smooth manifold. This counterexample also disproved a related conjecture, stating that for a closed manifold and a point in . A minimum dimensional counterexample to Ganea’s conjecture was constructed by Don Stanley and Hugo Rodríguez Ordóñez in 2010. This work raises the question: For which spaces X is the Ganea condition, , satisfied? It has been conjectured that these are precisely the spaces X for which equals a related invariant, (Wikipedia).
Lucile Vandembroucq (8/25/22): On the weak topological complexity and the TC-Ganea conjecture
By analogy with the classical Ganea conjecture, which has been disproved by N. Iwase, the TC-Ganea conjecture asks whether the equality TC(X x S^n)=TC(X)+TC(S^n) holds for all finite CW complexes X and all positive integers n. In a previous work in collaboration with J. González and M. Gra
From playlist Topological Complexity Seminar
What is the Riemann Hypothesis?
This video provides a basic introduction to the Riemann Hypothesis based on the the superb book 'Prime Obsession' by John Derbyshire. Along the way I look at convergent and divergent series, Euler's famous solution to the Basel problem, and the Riemann-Zeta function. Analytic continuation
From playlist Mathematics
Alexander Dranishnikov (9/22/22): On the LS-category of group homomorphisms
In 50s Eilenberg and Ganea proved that the Lusternik-Schnirelmann category of a discrete group Γ equals its cohomological dimension, cat(Γ) = cd(Γ). We discuss a possibility of the similar equality cat(φ) = cd(φ) for group homomorphisms φ : Γ → Λ. We prove this equality for some classes of
From playlist Topological Complexity Seminar
(ML 19.2) Existence of Gaussian processes
Statement of the theorem on existence of Gaussian processes, and an explanation of what it is saying.
From playlist Machine Learning
A Beautiful Proof of Ptolemy's Theorem.
Ptolemy's Theorem seems more esoteric than the Pythagorean Theorem, but it's just as cool. In fact, the Pythagorean Theorem follows directly from it. Ptolemy used this theorem in his astronomical work. Google for the historical details. Thanks to this video for the idea of this visual
From playlist Mathy Videos
Joe Neeman: Gaussian isoperimetry and related topics II
The Gaussian isoperimetric inequality gives a sharp lower bound on the Gaussian surface area of any set in terms of its Gaussian measure. Its dimension-independent nature makes it a powerful tool for proving concentration inequalities in high dimensions. We will explore several consequence
From playlist Winter School on the Interplay between High-Dimensional Geometry and Probability
Prime Numbers and their Mysterious Distribution (Prime Number Theorem)
Primes are the building blocks of math. But just how mysterious are they? Our study of prime numbers dates back to the ancient Greeks who first recognized that certain numbers can't be turned into rectangles, or that they can't be factored into any way. Over the years prime numbers have
From playlist Prime Numbers
Converse Pythagorean Theorem & Pythagorean Triples
I explain the Converse Pythagorean Theorem and what Pythagorean Triples are. Find free review test, useful notes and more at http://www.mathplane.com If you'd like to make a donation to support my efforts look for the "Tip the Teacher" button on my channel's homepage www.YouTube.com/Profro
From playlist Geometry
The Prime Number Theorem, an introduction ← Number Theory
An introduction to the meaning and history of the prime number theorem - a fundamental result from analytic number theory. Narrated by Cissy Jones Artwork by Kim Parkhurst, Katrina de Dios and Olga Reukova Written & Produced by Michael Harrison & Kimberly Hatch Harrison ♦♦♦♦♦♦♦♦♦♦ Ways t
From playlist Number Theory
Breaking the Softmax Bottleneck via Learnable Monotonic Pointwise Non-linearities | AISC
For slides and more information on the paper, visit https://aisc.ai.science/events/2019-10-08 Discussion lead: Octavian Ganea
From playlist Math and Foundations
Joe Neeman: Gaussian isoperimetry and related topics I
The Gaussian isoperimetric inequality gives a sharp lower bound on the Gaussian surface area of any set in terms of its Gaussian measure. Its dimension-independent nature makes it a powerful tool for proving concentration inequalities in high dimensions. We will explore several consequence
From playlist Winter School on the Interplay between High-Dimensional Geometry and Probability
Mee Sreyobhilashi Full Length Telugu Movie | Rajendra Prasad, RaghuBabu | #TeluguFullMovies
Mee Sreyobhilashi Telugu Full Movie Starring Rajendra Prasad, Raghubabu, Krishna Bhagawan, Naresh, Medha, Dhanush, Roopa Kaur among others. Mee Sreyobhilashi Telugu Film Directed by Y. Eshwara Reddy and Produced by Dr. Y. Sonia Reddy. Music Composed by Koti #TeluguMovies #MeeSreyobhilashi
From playlist Telugu Movies
Recent developments in non-commutative Iwasawa theory I - David Burns
David Burns March 25, 2011 For more videos, visit http://video.ias.edu
From playlist Mathematics
Giles Gardam: Kaplansky's conjectures
Talk by Giles Gardam in the Global Noncommutative Geometry Seminar (Americas) https://globalncgseminar.org/talks/3580/ on September 17, 2021.
From playlist Global Noncommutative Geometry Seminar (Americas)
Giles Gardam - Kaplansky's conjectures
Kaplansky made various related conjectures about group rings, especially for torsion-free groups. For example, the zero divisors conjecture predicts that if K is a field and G is a torsion-free group, then the group ring K[G] has no zero divisors. I will survey what is known about the conj
From playlist Talks of Mathematics Münster's reseachers
Gonçalo Tabuada - 1/3 Noncommutative Counterparts of Celebrated Conjectures
Some celebrated conjectures of Beilinson, Grothendieck, Kimura, Tate, Voevodsky, Weil, and others, play a key central role in algebraic geometry. Notwithstanding the effort of several generations of mathematicians, the proof of (the majority of) these conjectures remains illusive. The aim
From playlist Summer School 2020: Motivic, Equivariant and Non-commutative Homotopy Theory
Explicit formulae for Gross-Stark units and Hilbert’s 12th problem by Mahesh Kakde
PERFECTOID SPACES ORGANIZERS: Debargha Banerjee, Denis Benois, Chitrabhanu Chaudhuri, and Narasimha Kumar Cheraku DATE & TIME: 09 September 2019 to 20 September 2019 VENUE: Madhava Lecture Hall, ICTS, Bangalore Scientific committee: Jacques Tilouine (University of Paris, France) Eknath
From playlist Perfectoid Spaces 2019
Explicit formulae for Stark Units and Hilbert's 12th problem - Samit Dasgupta
Joint IAS/Princeton University Number Theory Seminar Topic: Explicit formulae for Stark Units and Hilbert's 12th problem Speaker: Samit Dasgupta Affiliation: Duke University Date: October 11, 2018 For more video please visit http://video.ias.edu
From playlist Mathematics
Pythagorean Theorem II (visual proof)
This is a short, animated visual proof of the Pythagorean theorem (the right triangle theorem) using a dissection of a square in two different ways. This theorem states the square of the hypotenuse of a right triangle is equal to the sum of squares of the two other side lengths. #mathshort
From playlist Pythagorean Theorem