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Difference between revisions of "Fejér singular integral"

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An integral of the form
 
An integral of the form
  
<table class="eq" style="width:100%;"> <tr><td valign="top" style="width:94%;text-align:center;"><img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/f/f038/f038350/f0383501.png" /></td> </tr></table>
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$$\sigma_n(f,x)=\frac1\pi\int\limits_{-\pi}^\pi f(x+t)\Phi_n(t)dt,$$
  
 
where
 
where
  
<table class="eq" style="width:100%;"> <tr><td valign="top" style="width:94%;text-align:center;"><img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/f/f038/f038350/f0383502.png" /></td> </tr></table>
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$$\Phi_n(t)=\frac{1}{2(n+1)}\frac{\sin^2(n+1)t/2}{\sin^2t/2}$$
  
is the Fejér kernel. The Fejér singular integral is an integral representation of the Fejér sums (cf. [[Fejér sum|Fejér sum]]) <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/f/f038/f038350/f0383503.png" />.
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is the Fejér kernel. The Fejér singular integral is an integral representation of the Fejér sums (cf. [[Fejér sum|Fejér sum]]) $\sigma_n(f,x)$.
  
 
For references see [[Fejér sum|Fejér sum]].
 
For references see [[Fejér sum|Fejér sum]].

Latest revision as of 14:13, 31 July 2014

An integral of the form

$$\sigma_n(f,x)=\frac1\pi\int\limits_{-\pi}^\pi f(x+t)\Phi_n(t)dt,$$

where

$$\Phi_n(t)=\frac{1}{2(n+1)}\frac{\sin^2(n+1)t/2}{\sin^2t/2}$$

is the Fejér kernel. The Fejér singular integral is an integral representation of the Fejér sums (cf. Fejér sum) $\sigma_n(f,x)$.

For references see Fejér sum.

How to Cite This Entry:
Fejér singular integral. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Fej%C3%A9r_singular_integral&oldid=22409
This article was adapted from an original article by S.A. Telyakovskii (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article