Unsolved problems in number theory | Conjectures

Hall's conjecture

In mathematics, Hall's conjecture is an open question, as of 2015, on the differences between perfect squares and perfect cubes. It asserts that a perfect square y2 and a perfect cube x3 that are not equal must lie a substantial distance apart. This question arose from consideration of the Mordell equation in the theory of integer points on elliptic curves. The original version of Hall's conjecture, formulated by Marshall Hall, Jr. in 1970, says that there is a positive constant C such that for any integers x and y for which y2 ≠ x3, Hall suggested that perhaps C could be taken as 1/5, which was consistent with all the data known at the time the conjecture was proposed. Danilov showed in 1982 that the exponent 1/2 on the right side (that is, the use of |x|1/2) cannot be replaced by any higher power: for no δ > 0 is there a constant C such that |y2 - x3| > C|x|1/2 + δ whenever y2 ≠ x3. In 1965, Davenport proved an analogue of the above conjecture in the case of polynomials: if f(t) and g(t) are nonzero polynomials over C such that g(t)3 ≠ f(t)2 in C[t], then The weak form of Hall's conjecture, stated by Stark and Trotter around 1980, replaces the square root on the right side of the inequality by any exponent less than 1/2: for any ε > 0, there is some constant c(ε) depending on ε such that for any integers x and y for which y2 ≠ x3, The original, strong, form of the conjecture with exponent 1/2 has never been disproved, although it is no longer believed to be true and the term Hall's conjecture now generally means the version with the ε in it. For example, in 1998, Noam Elkies found the example 4478849284284020423079182 - 58538865167812233 = -1641843, for which compatibility with Hall's conjecture would require C to be less than .0214 ≈ 1/50, so roughly 10 times smaller than the original choice of 1/5 that Hall suggested. The weak form of Hall's conjecture would follow from the ABC conjecture. A generalization to other perfect powers is Pillai's conjecture. The table below displays the known cases with . Note that y can be computed as thenearest integer to x3/2. (Wikipedia).

Video thumbnail

Albert Einstein, Holograms and Quantum Gravity

In the latest campaign to reconcile Einstein’s theory of gravity with quantum mechanics, many physicists are studying how a higher dimensional space that includes gravity arises like a hologram from a lower dimensional particle theory. Read about the second episode of the new season here:

From playlist In Theory

Video thumbnail

What is General Relativity? Lesson 69: The Einstein Equation

What is General Relativity? Lesson 69: The Einstein Equation Having done so much work with the Einstein tensor, the interpretation of the Einstein equation is almost anti-climatic! The hard part is finding the Newtonian limit in order to understand the constant of proportionality between

From playlist What is General Relativity?

Video thumbnail

Quantum Foam

The laws of quantum mechanics and relativity are quite perplexing however it is when the two theories are merged that things get really confusing. This combined theory predicts that empty space isn’t empty at all – it’s a seething and bubbling cauldron of matter and antimatter particles s

From playlist Quantum Physics

Video thumbnail

Loop Quantum Gravity

The inability of scientists to create a theory of quantum gravity arises from long-standing tensions between general relativity and quantum mechanics. There have been few approaches with any success. In this video, Fermilab’s Dr. Don Lincoln explains one of the few promising ideas, calle

From playlist Quantum Physics

Video thumbnail

Quantum field theory, Lecture 2

This winter semester (2016-2017) I am giving a course on quantum field theory. This course is intended for theorists with familiarity with advanced quantum mechanics and statistical physics. The main objective is introduce the building blocks of quantum electrodynamics. Here in Lecture 2

From playlist Quantum Field Theory

Video thumbnail

Schrodinger Equation Explained - Physics FOR BEGINNERS (can YOU understand this?)

EVEN YOU can understand what this fundamental equation of Physics actually means! Hey you lot, how's it going? I'm back with another Physics video. This time, we're discussing the Schrödinger Equation (yes that's right, Schrödinger of dead/alive cat fame). This equation is the cornerstone

From playlist Quantum Physics by Parth G

Video thumbnail

Quantum Mathematics and the Fate of Space, Time and Matter - Robbert Dijkgraaf

The elementary particles that make up the bizarre quantum world not only represents a more fundamental description of nature, they also inspires a new realm of mathematics that might be called "quantum mathematics." This turns out to be a powerful tool to solve deep outstanding mathematica

From playlist Mathematics Research Center

Video thumbnail

What is the Schrödinger Equation? A basic introduction to Quantum Mechanics

This video provides a basic introduction to the Schrödinger equation by exploring how it can be used to perform simple quantum mechanical calculations. After explaining the basic structure of the equation, the infinite square well potential is used as a case study. The separation of variab

From playlist Quantum Physics

Video thumbnail

Experimentalist Vs. Theorist on Einstein's General Theory of Relativity

Einstein's theories provided elegant explanations for existing phenomena—but he didn't quite hit the big time until experiments during a solar eclipse verified some of the predictions of his general theory of relativity. In this clip from the 2015 World Science Festival program "Reality Si

From playlist The Life and Work of Albert Einstein

Video thumbnail

cohomology of GL(N), adjoint Selmer groups and simplicial deformation rings by Jacques Tilouine

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

Video thumbnail

Diophantine Geometry - Rafael von Kenel

Rafael von Kenel ETH Zurich; Institute for Advanced Study October 7, 2011 For more videos, visit http://video.ias.edu

From playlist Mathematics

Video thumbnail

Mean field approximations to n-body projection Hamiltonians in FQHE by Sreejith G J

Indian Statistical Physics Community Meeting 2018 DATE:16 February 2018 to 18 February 2018 VENUE:Ramanujan Lecture Hall, ICTS Bangalore This is an annual discussion meeting of the Indian statistical physics community which is attended by scientists, postdoctoral fellows, and graduate s

From playlist Indian Statistical Physics Community Meeting 2018

Video thumbnail

Feng Luo: Recent developments in discrete conformal geometry of surfaces

CATS 2021 Online Seminar Feng Luo, Rutgers University Abstract: Discrete conformal geometry of surfaces attempts to establish computable discretizations of classical Riemann surface theory. This talk will focus on answering questions like, what are the discrete conformal equivalences a

From playlist Computational & Algorithmic Topology (CATS 2021)

Video thumbnail

Pere Ara: Crossed products and the Atiyah problem

Talk by Pere Are in Global Noncommutative Geometry Seminar (Americas) https://globalncgseminar.org/talks/crossed-products-and-the-atiyah-problem/ on March 19, 2021.

From playlist Global Noncommutative Geometry Seminar (Americas)

Video thumbnail

Two conjectures of Ringel, by Katherine Staden

CMSA Combinatorics Seminar, 22 July 2020

From playlist CMSA Combinatorics Seminar

Video thumbnail

Maria Chudnovsky: Induced cycles and coloring

Find this video and other talks given by worldwide mathematicians on CIRM's Audiovisual Mathematics Library: http://library.cirm-math.fr. And discover all its functionalities: - Chapter markers and keywords to watch the parts of your choice in the video - Videos enriched with abstracts, b

From playlist Combinatorics

Video thumbnail

Thomas Fernique - Maximally Dense Sphere Packings

It is well known that to cover the greatest proportion of the Euclidean plane with identical disks, we have to center these disks in a triangular grid. This problem can be generalized in two directions: in higher dimensions or with different sizes of disks. The first direction has been the

From playlist Combinatorics and Arithmetic for Physics: special days

Video thumbnail

On exceptional zero conjecture (Mazur-Tate-Teitelbaum) by Srilakshmi Krishnamoorthy

12 December 2016 to 22 December 2016 VENUE : Madhava Lecture Hall, ICTS Bangalore The Birch and Swinnerton-Dyer conjecture is a striking example of conjectures in number theory, specifically in arithmetic geometry, that has abundant numerical evidence but not a complete general solution.

From playlist Theoretical and Computational Aspects of the Birch and Swinnerton-Dyer Conjecture

Video thumbnail

Beyond Einstein: In Search of the Ultimate Explanation

Albert Einstein spent his last thirty years unsuccessfully searching for a ‘unified theory’ — a single master principle to describe everything in the universe, from tiny subatomic particles to immense clusters of galaxies. In the decades since, generations of researchers have continued wor

From playlist Explore the World Science Festival

Related pages

Elliptic curve | Pillai's conjecture | Mathematics | Square number