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Difference between revisions of "Defining operator"

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''for a sequence <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/d/d030/d030650/d0306501.png" />''
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{{TEX|done}}
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''for a sequence $x=\{x_p\}$''
  
An operator <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/d/d030/d030650/d0306502.png" /> in a space of sequences having the form
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An operator $M$ in a space of sequences having 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/d/d030/d030650/d0306503.png" /></td> </tr></table>
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$$(Mx)_p=\sum_{-l}^{+l}m_jx_{p-j};$$
  
<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/d/d030/d030650/d0306504.png" /></td> </tr></table>
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$$m_j=\overline{m_{-j}},\quad\sum_{-l}^{+l}m_j\lambda^j\leq0,\quad|\lambda|=1;$$
  
converting the sequence <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/d/d030/d030650/d0306505.png" /> to some [[Positive sequence|positive sequence]].
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converting the sequence $x$ to some [[Positive sequence|positive sequence]].

Latest revision as of 16:36, 13 November 2014

for a sequence $x=\{x_p\}$

An operator $M$ in a space of sequences having the form

$$(Mx)_p=\sum_{-l}^{+l}m_jx_{p-j};$$

$$m_j=\overline{m_{-j}},\quad\sum_{-l}^{+l}m_j\lambda^j\leq0,\quad|\lambda|=1;$$

converting the sequence $x$ to some positive sequence.

How to Cite This Entry:
Defining operator. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Defining_operator&oldid=11763
This article was adapted from an original article by N.K. Nikol'skiiB.S. Pavlov (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article