Diophantine approximation | Theorems in number theory

Hurwitz's theorem (number theory)

In number theory, Hurwitz's theorem, named after Adolf Hurwitz, gives a bound on a Diophantine approximation. The theorem states that for every irrational number ξ there are infinitely many relatively prime integers m, n such that The condition that ξ is irrational cannot be omitted. Moreover the constant is the best possible; if we replace by any number and we let (the golden ratio) then there exist only finitely many relatively prime integers m, n such that the formula above holds. The theorem is equivalent to the claim that the Markov constant of every number is larger than . (Wikipedia).

Video thumbnail

Maxim Kazarian - 3/3 Mathematical Physics of Hurwitz numbers

Hurwitz numbers enumerate ramified coverings of a sphere. Equivalently, they can be expressed in terms of combinatorics of the symmetric group; they enumerate factorizations of permutations as products of transpositions. It turns out that these numbers obey a huge num

From playlist ­­­­Physique mathématique des nombres de Hurwitz pour débutants

Video thumbnail

Maxim Kazarian - 1/3 Mathematical Physics of Hurwitz numbers

Hurwitz numbers enumerate ramified coverings of a sphere. Equivalently, they can be expressed in terms of combinatorics of the symmetric group; they enumerate factorizations of permutations as products of transpositions. It turns out that these numbers obey a huge num

From playlist ­­­­Physique mathématique des nombres de Hurwitz pour débutants

Video thumbnail

Maxim Kazarian - 2/3 Mathematical Physics of Hurwitz numbers

Hurwitz numbers enumerate ramified coverings of a sphere. Equivalently, they can be expressed in terms of combinatorics of the symmetric group; they enumerate factorizations of permutations as products of transpositions. It turns out that these numbers obey a huge num

From playlist ­­­­Physique mathématique des nombres de Hurwitz pour débutants

Video thumbnail

Dimitri Zvonkine - Hurwitz numbers, the ELSV formula, and the topological recursion

We will use the example of Hurwitz numbers to make an introduction into the intersection theory of moduli spaces of curves and into the subject of topological recursion.

From playlist ­­­­Physique mathématique des nombres de Hurwitz pour débutants

Video thumbnail

Theory of numbers: Gauss's lemma

This lecture is part of an online undergraduate course on the theory of numbers. We describe Gauss's lemma which gives a useful criterion for whether a number n is a quadratic residue of a prime p. We work it out explicitly for n = -1, 2 and 3, and as an application prove some cases of Di

From playlist Theory of numbers

Video thumbnail

Number theory Full Course [A to Z]

Number theory (or arithmetic or higher arithmetic in older usage) is a branch of pure #mathematics devoted primarily to the study of the integers and integer-valued functions. Number theorists study prime numbers as well as the properties of objects made out of integers (for example, ratio

From playlist Number Theory

Video thumbnail

Dimitri Zvonkine - On two ELSV formulas

The ELSV formula (discovered by Ekedahl, Lando, Shapiro and Vainshtein) is an equality between two numbers. The first one is a Hurwitz number that can be defined as the number of factorizations of a given permutation into transpositions. The second is the integral of a characteristic class

From playlist 4th Itzykson Colloquium - Moduli Spaces and Quantum Curves

Video thumbnail

Recent progress in multiplicative number theory – Kaisa Matomäki & Maksym Radziwiłł – ICM2018

Number Theory Invited Lecture 3.5 Recent progress in multiplicative number theory Kaisa Matomäki & Maksym Radziwiłł Abstract: Multiplicative number theory aims to understand the ways in which integers factorize, and the distribution of integers with special multiplicative properties (suc

From playlist Number Theory

Video thumbnail

Rahul Pandharipande - Enumerative Geometry of Curves, Maps, and Sheaves 2/5

The main topics will be the intersection theory of tautological classes on moduli space of curves, the enumeration of stable maps via Gromov-Witten theory, and the enumeration of sheaves via Donaldson-Thomas theory. I will cover a mix of classical and modern results. My goal will be, by th

From playlist 2021 IHES Summer School - Enumerative Geometry, Physics and Representation Theory

Video thumbnail

John Voight, Belyi maps in number theory: a survey

VaNTAGe Seminar, August 17, 2021 License CC-BY-NC-SA

From playlist Belyi maps and Hurwitz spaces

Video thumbnail

David Zureick-Brown, Moduli spaces and arithmetic statistics

VaNTAGe seminar on March 3, 2020 License: CC-BY-NC-SA Closed captions provided by Andrew Sutherland.

From playlist Class groups of number fields

Video thumbnail

Theory of numbers: Congruences: Euler's theorem

This lecture is part of an online undergraduate course on the theory of numbers. We prove Euler's theorem, a generalization of Fermat's theorem to non-prime moduli, by using Lagrange's theorem and group theory. As an application of Fermat's theorem we show there are infinitely many prim

From playlist Theory of numbers

Video thumbnail

Algebraic geometry 46: Examples of Hurwitz curves

This lecture is part of an online algebraic geometry course, based on chapter I of "Algebraic geometry" by Hartshorne. It gives examples of complex curves of genus 2 and 3 with the largest possible symmetry groups .

From playlist Algebraic geometry I: Varieties

Video thumbnail

David Roberts, Hurwitz Belyi maps

VaNTAGe seminar, October 12, 2021 License: CC-BY-NC-SA

From playlist Belyi maps and Hurwitz spaces

Video thumbnail

Edray Goins, Critical points of toroidal Belyi maps

VaNTAGe seminar, August 31, 2021 License CC-BY-NC-SA

From playlist Belyi maps and Hurwitz spaces

Video thumbnail

Jeremy Booher, Can you hear the shape of a curve

VaNTAGe seminar, on Nov 24, 2020 License: CC-BY-NC-SA.

From playlist ICERM/AGNTC workshop updates

Video thumbnail

[BOURBAKI 2019] Homology of Hurwitz spaces and the Cohen–Lenstra (...)- Randal-Williams - 15/06/19

Oscar RANDAL-WILLIAMS Homology of Hurwitz spaces and the Cohen–Lenstra heuristic for function fields, after Ellenberg, Venkatesh, and Westerland Ellenberg, Venkatesh, and Westerland have established a weak form of the function field analogue of the Cohen–Lenstra heuristic, on the distrib

From playlist BOURBAKI - 2019

Video thumbnail

Integral points on Markoff-type cubic surfaces - Amit Ghosh

Special Seminar Topic: Integral points on Markoff-type cubic surfaces Speaker: Amit Ghosh Affiliation: Oklahoma State University Date: December 8, 2017 For more videos, please visit http://video.ias.edu

From playlist Mathematics

Video thumbnail

Theory of numbers: Multiplicative functions

This lecture is part of an online undergraduate course on the theory of numbers. Multiplicative functions are functions such that f(mn)=f(m)f(n) whenever m and n are coprime. We discuss some examples, such as the number of divisors, the sum of the divisors, and Euler's totient function.

From playlist Theory of numbers

Video thumbnail

Rahul Pandharipande - Enumerative Geometry of Curves, Maps, and Sheaves 1/5

The main topics will be the intersection theory of tautological classes on moduli space of curves, the enumeration of stable maps via Gromov-Witten theory, and the enumeration of sheaves via Donaldson-Thomas theory. I will cover a mix of classical and modern results. My goal will be, by th

From playlist 2021 IHES Summer School - Enumerative Geometry, Physics and Representation Theory

Related pages

Markov constant | Diophantine approximation | Irrational number | Coprime integers | G. H. Hardy | Golden ratio | Number theory