Difference between revisions of "Main Page"

From MWiki
Jump to: navigation, search
(Green's theorem)
m (→‎Reversion theorem of Taylor series)
(47 intermediate revisions by the same user not shown)
Line 1: Line 1:
 
__NOTOC__
 
__NOTOC__
 
= Welcome to MWiki =
 
= Welcome to MWiki =
−
== Theorem of the month ==
+
== Theorems of the month ==
−
=== Green's theorem ===
+
=== Counting theorem for algebraic numbers ===
  
−
Given neighbourhood relations <math>B \subseteq {A}^{2}</math> for some simply connected <math>h</math>-set <math>A \subseteq {}^{(\omega)}\mathbb{R}^{2}</math>, infinitesimal <math>h = |dBx|= |dBy| = |\curvearrowright B \gamma(t) - \gamma(t)| = \mathcal{O}({\hat{\omega}}^{m})</math>, sufficiently large <math>m \in \mathbb{N}^{*}, (x, y) \in A, {A}^{-} := \{(x, y) \in A : (x + h, y + h) \in A\}</math>, and a simply closed path <math>\gamma: [a, b[\rightarrow \partial A</math> followed anticlockwise, choosing <math>\curvearrowright B \gamma(t) = \gamma(\curvearrowright D t)</math> for <math>t \in [a, b[, D \subseteq {[a, b]}^{2}</math>, the following equation holds for sufficiently <math>\alpha</math>-continuous functions <math>u, v: A \rightarrow \mathbb{R}</math> with not necessarily continuous partial derivatives <math>\partial Bu/\partial Bx, \partial Bu/\partial By, \partial Bv/\partial Bx</math> and <math>\partial Bv/\partial By</math>:<div style="text-align:center;"><math>\int\limits_{\gamma }{(u\,dBx+v\,dBy)}=\int\limits_{(x,y)\in {{A}^{-}}}{\left( \frac{\partial Bv}{\partial Bx}-\frac{\partial Bu}{\partial By} \right)dB(x,y)}.</math></div>
+
The number <math>\mathbb{A}(m, n)</math> of algebraic numbers of polynomial or series degree <math>m</math> and thus in general for the Riemann zeta function <math>\zeta</math> asymptotically satisfies the equation <math>\mathbb{A}(m, n) = \widetilde{\zeta(\grave{m})}\,z(m){{(2n+1)}^{m}}\left( n+\mathcal{O}({_e}n) \right)</math>, where <math>z(m)</math> is the average number of zeros of a polynomial or series.
  
 
==== Proof: ====
 
==== Proof: ====
−
Wlog the case <math>A := \{(x, y) : r \le x \le s, f(x) \le y \le g(x)\}, r, s \in {}^{(\omega)}\mathbb{R}, f, g : \partial A \rightarrow {}^{(\omega)}\mathbb{R}</math> is proved, since the proof is analogous for each case rotated by <math>\iota</math>, and every simply connected <math>h</math>-set is a union of such sets. It is simply shown that<div style="text-align:center;"><math>\int\limits_{\gamma }{u\,dBx}=-\int\limits_{(x,y)\in {{A}^{-}}}{\frac{\partial Bu}{\partial By}dB(x,y)}</math></div>since the other relation is given analogously. Since the regions of <math>\gamma</math> where <math>dBx = 0</math> do not contribute to the integral, for negligibly small <math>t := h(u(s, g(s)) - u(r, g(r)))</math>, it holds that<div style="text-align:center;"><math>-\int\limits_{\gamma }{u\,dBx}-t=\int\limits_{r}^{s}{u(x,g(x))dBx}-\int\limits_{r}^{s}{u(x,f(x))dBx}=\int\limits_{r}^{s}{\int\limits_{f(x)}^{g(x)}{\frac{\partial Bu}{\partial By}}dBydBx}=\int\limits_{(x,y)\in {{A}^{-}}}{\frac{\partial Bu}{\partial By}dB(x,y)}.\square</math></div>
+
The case <math>m = 1</math> requires by <ref name="Scheid">[[w:Harald Scheid|<span class="wikipedia">Scheid, Harald</span>]]: ''Zahlentheorie'' : 1st Ed.; 1991; Bibliographisches Institut; Mannheim; ISBN 9783411148417, p. 323.</ref> the error term <math>\mathcal{O}({_e}n n)</math> and represents the number <math>4{+}_{k=1}^{n}{\varphi (k)}-1</math> by the <math>\varphi</math>-function. For <math>m > 1</math>, the divisibility conditions neither change the error term <math>\mathcal{O}({_e}n)</math> nor the leading term. Polynomials or series such that <math>\text{gcd}({a}_{0}, {a}_{1}, ..., {a}_{m}) \ne 1</math> are excluded by <math>1/\zeta(\grave{m})</math>: The latter is given by taking the product over the prime numbers <math>p</math> of all <math>(1 - {p}^{-\grave{m}})</math> absorbing here multiples of <math>p</math> and representing sums of geometric series.<math>\square</math>
 +
 
 +
=== Brocard's theorem ===
 +
It holds that <math>\{(m, n) \in {}^{\omega} \mathbb{N}^2 : n! + 1 = m^2\} = \{(5, 4), (11, 5), (71, 7)\}.</math>
 +
 
 +
==== Proof: ====
 +
From <math>n! = \acute{m}\grave{m}</math>, it follows that <math>m = \hat{r} \pm 1</math> für <math>r \in {}^{\omega} \mathbb{N}^{*}</math> and <math>n \ge 3</math>. Thus <math>n! = \hat{r}(\hat{r}\pm2) = 8s(\hat{s} \pm 1)</math> holds for <math>s \in {}^{\omega} \mathbb{N}^{*}</math>. Let <math>2^q \mid n!</math> and <math>2^{\grave{q}} \nmid n!</math> for maximal <math>q \in {}^{\omega} \mathbb{N}^{*}</math>. Therefore <math>n! = 2^q(\hat{u} + 1)</math> holds for <math>u \in {}^{\omega} \mathbb{N}^{*}</math> and necessarily <math>n! = 2^q(2^{q-2} \pm 1)</math>. Then the prime factorisation of <math>n!</math> requires <math>n \le 7</math> giving the claim.<math>\square</math>
 +
 
 +
=== Reversion theorem of Taylor series ===
 +
For <math>y \in f(\mathbb{D}), y(a) = b</math> and <math>y^{\prime}(a) \ne 0</math>, [[w:Lagrange_inversion_theorem#Lagrange–Bürmann_formula|<span class="wikipedia">Bürmann's theorem</span>]] yields:<div style="text-align:center;"><math>f^{-1}(y) = a + \tilde{n} {\LARGE{\textbf{+}}}_{m=1}^n{\widetilde{m}{\tilde{\varepsilon}}^{\acute{m}}(y - b)^m({\tilde{u}}^{\acute{m}k})^T(f(\varepsilon u^k + a)^{-m})}+\mathcal{O}(\varepsilon^n).\square</math></div>
  
 
== Recommended reading ==
 
== Recommended reading ==
  
 
[https://en.calameo.com/books/003777977258f7b4aa332 Nonstandard Mathematics]
 
[https://en.calameo.com/books/003777977258f7b4aa332 Nonstandard Mathematics]
 +
 +
== References ==
 +
<references />
  
 
[[de:Hauptseite]]
 
[[de:Hauptseite]]

Revision as of 00:22, 18 July 2024

Welcome to MWiki

Theorems of the month

Counting theorem for algebraic numbers

The number [math]\displaystyle{ \mathbb{A}(m, n) }[/math] of algebraic numbers of polynomial or series degree [math]\displaystyle{ m }[/math] and thus in general for the Riemann zeta function [math]\displaystyle{ \zeta }[/math] asymptotically satisfies the equation [math]\displaystyle{ \mathbb{A}(m, n) = \widetilde{\zeta(\grave{m})}\,z(m){{(2n+1)}^{m}}\left( n+\mathcal{O}({_e}n) \right) }[/math], where [math]\displaystyle{ z(m) }[/math] is the average number of zeros of a polynomial or series.

Proof:

The case [math]\displaystyle{ m = 1 }[/math] requires by [1] the error term [math]\displaystyle{ \mathcal{O}({_e}n n) }[/math] and represents the number [math]\displaystyle{ 4{+}_{k=1}^{n}{\varphi (k)}-1 }[/math] by the [math]\displaystyle{ \varphi }[/math]-function. For [math]\displaystyle{ m \gt 1 }[/math], the divisibility conditions neither change the error term [math]\displaystyle{ \mathcal{O}({_e}n) }[/math] nor the leading term. Polynomials or series such that [math]\displaystyle{ \text{gcd}({a}_{0}, {a}_{1}, ..., {a}_{m}) \ne 1 }[/math] are excluded by [math]\displaystyle{ 1/\zeta(\grave{m}) }[/math]: The latter is given by taking the product over the prime numbers [math]\displaystyle{ p }[/math] of all [math]\displaystyle{ (1 - {p}^{-\grave{m}}) }[/math] absorbing here multiples of [math]\displaystyle{ p }[/math] and representing sums of geometric series.[math]\displaystyle{ \square }[/math]

Brocard's theorem

It holds that [math]\displaystyle{ \{(m, n) \in {}^{\omega} \mathbb{N}^2 : n! + 1 = m^2\} = \{(5, 4), (11, 5), (71, 7)\}. }[/math]

Proof:

From [math]\displaystyle{ n! = \acute{m}\grave{m} }[/math], it follows that [math]\displaystyle{ m = \hat{r} \pm 1 }[/math] für [math]\displaystyle{ r \in {}^{\omega} \mathbb{N}^{*} }[/math] and [math]\displaystyle{ n \ge 3 }[/math]. Thus [math]\displaystyle{ n! = \hat{r}(\hat{r}\pm2) = 8s(\hat{s} \pm 1) }[/math] holds for [math]\displaystyle{ s \in {}^{\omega} \mathbb{N}^{*} }[/math]. Let [math]\displaystyle{ 2^q \mid n! }[/math] and [math]\displaystyle{ 2^{\grave{q}} \nmid n! }[/math] for maximal [math]\displaystyle{ q \in {}^{\omega} \mathbb{N}^{*} }[/math]. Therefore [math]\displaystyle{ n! = 2^q(\hat{u} + 1) }[/math] holds for [math]\displaystyle{ u \in {}^{\omega} \mathbb{N}^{*} }[/math] and necessarily [math]\displaystyle{ n! = 2^q(2^{q-2} \pm 1) }[/math]. Then the prime factorisation of [math]\displaystyle{ n! }[/math] requires [math]\displaystyle{ n \le 7 }[/math] giving the claim.[math]\displaystyle{ \square }[/math]

Reversion theorem of Taylor series

For [math]\displaystyle{ y \in f(\mathbb{D}), y(a) = b }[/math] and [math]\displaystyle{ y^{\prime}(a) \ne 0 }[/math], Bürmann's theorem yields:

[math]\displaystyle{ f^{-1}(y) = a + \tilde{n} {\LARGE{\textbf{+}}}_{m=1}^n{\widetilde{m}{\tilde{\varepsilon}}^{\acute{m}}(y - b)^m({\tilde{u}}^{\acute{m}k})^T(f(\varepsilon u^k + a)^{-m})}+\mathcal{O}(\varepsilon^n).\square }[/math]

Recommended reading

Nonstandard Mathematics

References

  1. ↑ Scheid, Harald: Zahlentheorie : 1st Ed.; 1991; Bibliographisches Institut; Mannheim; ISBN 9783411148417, p. 323.
Retrieved from "https://en.mwiki.de/index.php?title=Main_Page&oldid=310"