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	<title>DNSS point - Revision history</title>
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	<updated>2026-05-21T12:19:05Z</updated>
	<subtitle>Revision history for this page on the wiki</subtitle>
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		<id>https://en.formulasearchengine.com/index.php?title=DNSS_point&amp;diff=23867&amp;oldid=prev</id>
		<title>en&gt;Helpful Pixie Bot: ISBNs (Build KE)</title>
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		<updated>2012-05-11T06:18:07Z</updated>

		<summary type="html">&lt;p&gt;ISBNs (Build KE)&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;In mathematics, a &amp;#039;&amp;#039;&amp;#039;Redheffer matrix&amp;#039;&amp;#039;&amp;#039;, studied by {{harvtxt|Redheffer|1977}}, is a [[(0,1) matrix]] whose entries &amp;#039;&amp;#039;a&amp;#039;&amp;#039;&amp;lt;sub&amp;gt;&amp;#039;&amp;#039;ij&amp;#039;&amp;#039;&amp;lt;/sub&amp;gt; are 1 if &amp;#039;&amp;#039;i&amp;#039;&amp;#039; divides &amp;#039;&amp;#039;j&amp;#039;&amp;#039; or if &amp;#039;&amp;#039;j&amp;#039;&amp;#039;&amp;amp;nbsp;=&amp;amp;nbsp;1; otherwise, &amp;#039;&amp;#039;a&amp;#039;&amp;#039;&amp;lt;sub&amp;gt;&amp;#039;&amp;#039;ij&amp;#039;&amp;#039;&amp;lt;/sub&amp;gt;&amp;amp;nbsp;=&amp;amp;nbsp;0.&lt;br /&gt;
&lt;br /&gt;
The [[determinant]] of the &amp;#039;&amp;#039;n&amp;#039;&amp;#039;x&amp;#039;&amp;#039;n&amp;#039;&amp;#039; [[square matrix|square]] Redheffer matrix is given by the [[Mertens function]] &amp;#039;&amp;#039;M&amp;#039;&amp;#039;(&amp;#039;&amp;#039;n&amp;#039;&amp;#039;).&lt;br /&gt;
&lt;br /&gt;
==Example==&lt;br /&gt;
The matrix below is the 12&amp;amp;nbsp;&amp;amp;times;&amp;amp;nbsp;12 Redheffer matrix.&lt;br /&gt;
:&amp;lt;math&amp;gt;\left(\begin{smallmatrix}&lt;br /&gt;
1 &amp;amp; 1 &amp;amp; 1 &amp;amp; 1 &amp;amp; 1 &amp;amp; 1 &amp;amp; 1 &amp;amp; 1 &amp;amp; 1 &amp;amp; 1 &amp;amp; 1 &amp;amp; 1 \\&lt;br /&gt;
1 &amp;amp; 1 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 1 \\&lt;br /&gt;
1 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1 \\&lt;br /&gt;
1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1 \\&lt;br /&gt;
1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 0 \\&lt;br /&gt;
1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1 \\&lt;br /&gt;
1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 \\&lt;br /&gt;
1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 \\&lt;br /&gt;
1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 \\&lt;br /&gt;
1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 &amp;amp; 0 \\&lt;br /&gt;
1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1 &amp;amp; 0 \\&lt;br /&gt;
1 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 0 &amp;amp; 1&lt;br /&gt;
\end{smallmatrix}\right)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
==References==&lt;br /&gt;
*{{Citation | authorlink=Raymond Redheffer | last1=Redheffer | first1=Ray | title=Numerische Methoden bei Optimierungsaufgaben, Band 3 (Tagung, Math. Forschungsinst., Oberwolfach, 1976) | publisher=Birkhäuser | location=Basel, Boston, Berlin | id={{MathSciNet | id = 0468170}} | year=1977 | chapter=Eine explizit lösbare Optimierungsaufgabe | pages=213–216}}&lt;br /&gt;
&lt;br /&gt;
==External links==&lt;br /&gt;
*{{MathWorld |title= Redheffer matrix|urlname=RedhefferMatrix}}&lt;br /&gt;
&lt;br /&gt;
[[Category:Matrices]]&lt;/div&gt;</summary>
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