Difference between revisions of "Main Page"

From MWiki
Jump to: navigation, search
m (RU method)
(Fundamental theorems)
Line 1: Line 1:
 
__NOTOC__
 
__NOTOC__
 
= Welcome to MWiki =
 
= Welcome to MWiki =
−
== Theorem of the month ==
+
== Theorems of the month ==
−
=== RU method ===
+
First fundamental theorem of exact differential and integral calculus for line integrals: The function <math>F(z)=\int\limits_{\gamma }{f(\zeta )dB\zeta }</math> where <math>\gamma: [d, x[C \rightarrow A \subseteq {}^{(\omega)}\mathbb{K}, C \subseteq \mathbb{R}, f: A \rightarrow {}^{(\omega)}\mathbb{K}, d \in [a, b[C</math>, and choosing <math>\curvearrowright B \gamma(x) = \gamma(\curvearrowright D x)</math> is exactly <math>B</math>-differentiable, and for all <math>x \in [a, b[C</math> and <math>z = \gamma(x)</math>
−
If <math>A \in {}^{\nu}\mathbb{Q}^{n \times n}</math> is regular in the linear system (LS) <math>Ax = b \in  {}^{\nu}\mathbb{Q}^{n}</math> for <math>n \in {}^{\nu}\mathbb{N}^*</math>, the ''root of unity method (<math>RU</math> method)'' computes <math>x \in {}^{\nu}\mathbb{Q}^{n}</math> for <math>A \in {}^{\nu}\mathbb{Q}^{n \times n}</math> in <math>\mathcal{O}(n^2)</math>.
 
  
−
=== Proof and algorithm ===
+
<div style="text-align:center;"><math>F' \curvearrowright B(z) = f(z).</math></div>
−
Let <math>R_1 := (r_{1jk}) = (r_{1kj}) = R_1^T \in {}^{\nu}\mathbb{C}^{n \times n}, n \in {}^{\nu}2\mathbb{N}^*, r_{11k} := 1</math> and for <math>j &gt; 1</math> as well as <math>n_{jk} := j + k - 3</math> both <math>r_{1jk} := \hat{n}e^{i\tau n_{jk}/n}</math> for <math>n_{jk} &lt; n</math> and <math>r_{1jk} := \hat{n}e^{i\tau(n_{jk} - \acute{n})/n}</math> for <math>n_{jk} \ge n</math>. Interchanging the first and <math>j</math>-th row resp. column position and correspondingly interchanging the remaining row and column positions yields matrices <math>R_j = R_j^T</math> for <math>j &gt; 1</math>. Let <math>\delta_{jk}</math> be the Kronecker delta and <math>A := (a_{jk})</math>.
 
  
−
If <math>a_{jk} \le 0</math> is given for at least one couple <math>(j, k)</math>, then compute the sums <math>s_0 := \sum\limits_{j=1}^m{b_j\varepsilon^j}</math> for an arbitrary transcendental number <math>\varepsilon</math> and <math>s_k := \sum\limits_{j=1}^m{a_{jk}\varepsilon^j} \ne 0</math> for all <math>k</math>. Replace <math>x_k</math> by <math>-x_k</math> for <math>s_k &lt; 0</math>. Add a multiple of <math>s^Tx</math> resp. <math>s_0</math> to <math>Ax = b</math>, such that <math>a_{jk} &gt; 0</math> holds for all <math>(j, k)</math>. Let <math>b_j = 1</math> for all <math>j</math> wlog. For <math>D_j := (d_{jk}), d_{jk} = \delta_{jk}⁄a_{jk}, C_j := D_j R_j</math> and <math>x_k^{(0)} := \hat{n}/ \max_j a_{jk}</math>, let <math>x^{(\grave{m})} = x^{(m)} + C_j^{-1}(b - Ax^{(m)}).\square</math>
 
  
−
=== Corollary ===
+
Proof: <math>dB(F(z))=\int\limits_{t\in [d,x]C}{f(\gamma (t)){{{{\gamma }'}}_{\curvearrowright }}D(t)dDt}-\int\limits_{t\in [d,x[C}{f(\gamma (t)){{{{\gamma }'}}_{\curvearrowright }}D(t)dDt}=\int\limits_{x}{f(\gamma (t))\frac{\gamma (\curvearrowright Dt)-\gamma (t)}{\curvearrowright Dt-t}dDt}=f(\gamma (x)){{{\gamma }'}_{\curvearrowright }}D(x)dDx=\,f(\gamma (x))(\curvearrowright B\gamma (x)-\gamma (x))=f(z)dBz.\square</math>
−
The RU method allows to determine every eigenvalue and -vector of <math>Ax = \lambda x \in {}^{\nu}\mathbb{Q}^{n} + {}^{\nu}\mathbb{Q}^{n}</math> for <math>n \in {}^{\nu}2\mathbb{N}^*, \lambda \in {}^{\nu}\mathbb{Q}+ {i}^{\nu}\mathbb{Q}</math> and <math>A  \in {}^{\nu}\mathbb{Q}^{n \times n}</math> in <math>\mathcal{O}(n^2)</math> by putting <math>x^{\prime(\grave{m})} = C_j^{-1}AC_j x^{\prime(m)}.\square</math>
 
  
−
'''Remark:''' Extending the theorem to complex <math>A</math> and <math>b</math> is easy. By the Banach fixed-point theorem, the <math>RU</math> method converges linearly for every regular LS.
+
Second fundamental theorem of exact differential and integral calculus for line integrals: According to the conditions from above, we have with <math>\gamma: [a, b[C \rightarrow {}^{(\omega)}\mathbb{K}</math> that
−
== Recommended reading ==
 
  
 +
 +
<div style="text-align:center;"><math>F(\gamma (b))-F(\gamma (a))=\int\limits_{\gamma }{{{{{F}'}}_{\curvearrowright }}B(\zeta )dB\zeta }.</math></div>
 +
 +
 +
Proof: <math>F(\gamma (b))-F(\gamma (a))=\sum\limits_{t\in [a,b[C}{F(\curvearrowright B\,\gamma (t))}-F(\gamma (t))=\sum\limits_{t\in [a,b[C}{{{{{F}'}}_{\curvearrowright }}B(\gamma (t))(\curvearrowright B\,\gamma (t)-\gamma (t))}=\int\limits_{t\in [a,b[C}{{{{{F}'}}_{\curvearrowright }}B(\gamma (t)){{{{\gamma }'}}_{\curvearrowright }}D(t)dDt}=\int\limits_{\gamma }{{{{{F}'}}_{\curvearrowright }}B(\zeta )dB\zeta }.\square</math>
 +
 +
== Recommended readings ==
 
[https://en.calameo.com/books/003777977258f7b4aa332 Nonstandard Mathematics]
 
[https://en.calameo.com/books/003777977258f7b4aa332 Nonstandard Mathematics]
  
 
[[de:Hauptseite]]
 
[[de:Hauptseite]]

Revision as of 20:08, 23 November 2020

Welcome to MWiki

Theorems of the month

First fundamental theorem of exact differential and integral calculus for line integrals: The function [math]\displaystyle{ F(z)=\int\limits_{\gamma }{f(\zeta )dB\zeta } }[/math] where [math]\displaystyle{ \gamma: [d, x[C \rightarrow A \subseteq {}^{(\omega)}\mathbb{K}, C \subseteq \mathbb{R}, f: A \rightarrow {}^{(\omega)}\mathbb{K}, d \in [a, b[C }[/math], and choosing [math]\displaystyle{ \curvearrowright B \gamma(x) = \gamma(\curvearrowright D x) }[/math] is exactly [math]\displaystyle{ B }[/math]-differentiable, and for all [math]\displaystyle{ x \in [a, b[C }[/math] and [math]\displaystyle{ z = \gamma(x) }[/math]

[math]\displaystyle{ F' \curvearrowright B(z) = f(z). }[/math]


Proof: [math]\displaystyle{ dB(F(z))=\int\limits_{t\in [d,x]C}{f(\gamma (t)){{{{\gamma }'}}_{\curvearrowright }}D(t)dDt}-\int\limits_{t\in [d,x[C}{f(\gamma (t)){{{{\gamma }'}}_{\curvearrowright }}D(t)dDt}=\int\limits_{x}{f(\gamma (t))\frac{\gamma (\curvearrowright Dt)-\gamma (t)}{\curvearrowright Dt-t}dDt}=f(\gamma (x)){{{\gamma }'}_{\curvearrowright }}D(x)dDx=\,f(\gamma (x))(\curvearrowright B\gamma (x)-\gamma (x))=f(z)dBz.\square }[/math]

Second fundamental theorem of exact differential and integral calculus for line integrals: According to the conditions from above, we have with [math]\displaystyle{ \gamma: [a, b[C \rightarrow {}^{(\omega)}\mathbb{K} }[/math] that


[math]\displaystyle{ F(\gamma (b))-F(\gamma (a))=\int\limits_{\gamma }{{{{{F}'}}_{\curvearrowright }}B(\zeta )dB\zeta }. }[/math]


Proof: [math]\displaystyle{ F(\gamma (b))-F(\gamma (a))=\sum\limits_{t\in [a,b[C}{F(\curvearrowright B\,\gamma (t))}-F(\gamma (t))=\sum\limits_{t\in [a,b[C}{{{{{F}'}}_{\curvearrowright }}B(\gamma (t))(\curvearrowright B\,\gamma (t)-\gamma (t))}=\int\limits_{t\in [a,b[C}{{{{{F}'}}_{\curvearrowright }}B(\gamma (t)){{{{\gamma }'}}_{\curvearrowright }}D(t)dDt}=\int\limits_{\gamma }{{{{{F}'}}_{\curvearrowright }}B(\zeta )dB\zeta }.\square }[/math]

Recommended readings

Nonstandard Mathematics

Retrieved from "https://en.mwiki.de/index.php?title=Main_Page&oldid=171"