Rank and codimension: Difference between revisions

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<h2>IMPORTED REVISION FROM WIKISPACES</h2>
<h2>IMPORTED REVISION FROM WIKISPACES</h2>
This is an imported revision from Wikispaces. The revision metadata is included below for reference:<br>
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: This revision was by author [[User:genewardsmith|genewardsmith]] and made on <tt>2012-02-01 18:20:52 UTC</tt>.<br>
: This revision was by author [[User:guest|guest]] and made on <tt>2012-10-31 20:24:48 UTC</tt>.<br>
: The original revision id was <tt>297586378</tt>.<br>
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The [[http://en.wikipedia.org/wiki/Codimension|codimension]] or [[http://en.wikipedia.org/wiki/Free_abelian_group#Rank|co-rank]] of a temperament is the number of [[Comma|commas]] needed to completely define the temperament. If the temperament tempers the [[Harmonic Limit|p-limit]] just intonation group generated by the first n primes, then if it tempers out n-r independent commas, it will be of rank r and codimension n-r. The terminology can also be applied to [[just intonation subgroups]]. In all cases care must be taken to specify the exact just intonation group which is being tempered by the tempering out of a set of commas.
The [[http://en.wikipedia.org/wiki/Codimension|codimension]] or [[http://en.wikipedia.org/wiki/Free_abelian_group#Rank|co-rank]] of a temperament is the number of [[Comma|commas]] needed to completely define the temperament. If the temperament tempers the [[Harmonic Limit|p-limit]] just intonation group generated by the first n primes, then if it tempers out n-r independent commas, it will be of rank r and codimension n-r. The terminology can also be applied to [[just intonation subgroups]]. In all cases care must be taken to specify the exact just intonation group which is being tempered by the tempering out of a set of commas.


Looking only at the number of independent generators of a tuning can obscure its real nature, at least as it is being applied. For instance, a 31et tuning of meantone temperament, with a meantone fifth of 18\31 octaves, is of rank one in the sense that all the intervals in the tuning are generated from 1\31; however, it is being used as a rank two tuning. This issue can be gotten around by means of [[Abstract regular temperament|abstract regular temperaments]]; an abstract regular temperament is of rank r if it is defined by a [[Normal lists|normal val list]] of r vals, or equivalently by an r-multival. The abstractly characterized intervals of the abstract temperament can then be mapped to a tuning; if the mapping is to a rank one tuning such as 31et, that does not affect the rank of the temperament.</pre></div>
Looking only at the number of independent generators of a tuning can obscure its real nature, at least as it is being applied. For instance, a 31et tuning of meantone temperament, with a meantone fifth of 18\31 octaves, is of rank one in the sense that all the intervals in the tuning are generated from 1\31; however, it is being used as a rank two tuning. This issue can be gotten around by means of [[@http://et3allem.blogspot.com|abstract regular temperaments]]; an abstract regular temperament is of rank r if it is defined by a [[Normal lists|normal val list]] of r vals, or equivalently by an r-multival. The abstractly characterized intervals of the abstract temperament can then be mapped to a tuning; if the mapping is to a rank one tuning such as 31et, that does not affect the rank of the temperament.
 
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<h4>Original HTML content:</h4>
<h4>Original HTML content:</h4>
<div style="width:100%; max-height:400pt; overflow:auto; background-color:#f8f9fa; border: 1px solid #eaecf0; padding:0em"><pre style="margin:0px;border:none;background:none;word-wrap:break-word;width:200%;white-space: pre-wrap ! important" class="old-revision-html">&lt;html&gt;&lt;head&gt;&lt;title&gt;Rank and codimension&lt;/title&gt;&lt;/head&gt;&lt;body&gt;The &lt;em&gt;rank&lt;/em&gt; of a &lt;a class="wiki_link" href="/Regular%20Temperaments"&gt;regular temperament&lt;/a&gt; is the number of independent intervals, called &lt;em&gt;generators&lt;/em&gt;, which can be combined together to obtain any interval of the temperament. For instance, every interval of &lt;a class="wiki_link" href="/meantone"&gt;meantone&lt;/a&gt; can be obtained as a combination of a certain number of octaves up or down, plus a certain number of flattened meantone fifths up or down. The terminology comes from group theory; in the parlance of group theory, the intervals of a regular temperament comprise a &lt;a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Free_abelian_group#Rank" rel="nofollow"&gt;finitely generated free abelian group&lt;/a&gt; with a rank equal to the number of generators.&lt;br /&gt;
<div style="width:100%; max-height:400pt; overflow:auto; background-color:#f8f9fa; border: 1px solid #eaecf0; padding:0em"><pre style="margin:0px;border:none;background:none;word-wrap:break-word;width:200%;white-space: pre-wrap ! important" class="old-revision-html">&lt;html&gt;&lt;head&gt;&lt;title&gt;Rank and codimension&lt;/title&gt;&lt;/head&gt;&lt;body&gt;The &lt;em&gt;rank&lt;/em&gt; of a &lt;a class="wiki_link" href="/Regular%20Temperaments"&gt;regular temperament&lt;/a&gt; is the number of independent intervals, called &lt;em&gt;generators&lt;/em&gt;, which can be combined together to obtain any interval of the temperament. For instance, every interval of &lt;a class="wiki_link" href="/meantone"&gt;meantone&lt;/a&gt; can be obtained as a combination of a certain number of octaves up or down, plus a certain number of flattened meantone fifths up or down. The terminology comes from group theory; in the parlance of group theory, the intervals of a regular temperament comprise a &lt;a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Free_abelian_group#Rank" rel="nofollow"&gt;finitely generated free abelian group&lt;/a&gt; with a rank equal to the number of generators.&lt;br /&gt;
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The &lt;a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Codimension" rel="nofollow"&gt;codimension&lt;/a&gt; or &lt;a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Free_abelian_group#Rank" rel="nofollow"&gt;co-rank&lt;/a&gt; of a temperament is the number of &lt;a class="wiki_link" href="/Comma"&gt;commas&lt;/a&gt; needed to completely define the temperament. If the temperament tempers the &lt;a class="wiki_link" href="/Harmonic%20Limit"&gt;p-limit&lt;/a&gt; just intonation group generated by the first n primes, then if it tempers out n-r independent commas, it will be of rank r and codimension n-r. The terminology can also be applied to &lt;a class="wiki_link" href="/just%20intonation%20subgroups"&gt;just intonation subgroups&lt;/a&gt;. In all cases care must be taken to specify the exact just intonation group which is being tempered by the tempering out of a set of commas.&lt;br /&gt;
The &lt;a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Codimension" rel="nofollow"&gt;codimension&lt;/a&gt; or &lt;a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Free_abelian_group#Rank" rel="nofollow"&gt;co-rank&lt;/a&gt; of a temperament is the number of &lt;a class="wiki_link" href="/Comma"&gt;commas&lt;/a&gt; needed to completely define the temperament. If the temperament tempers the &lt;a class="wiki_link" href="/Harmonic%20Limit"&gt;p-limit&lt;/a&gt; just intonation group generated by the first n primes, then if it tempers out n-r independent commas, it will be of rank r and codimension n-r. The terminology can also be applied to &lt;a class="wiki_link" href="/just%20intonation%20subgroups"&gt;just intonation subgroups&lt;/a&gt;. In all cases care must be taken to specify the exact just intonation group which is being tempered by the tempering out of a set of commas.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Looking only at the number of independent generators of a tuning can obscure its real nature, at least as it is being applied. For instance, a 31et tuning of meantone temperament, with a meantone fifth of 18\31 octaves, is of rank one in the sense that all the intervals in the tuning are generated from 1\31; however, it is being used as a rank two tuning. This issue can be gotten around by means of &lt;a class="wiki_link" href="/Abstract%20regular%20temperament"&gt;abstract regular temperaments&lt;/a&gt;; an abstract regular temperament is of rank r if it is defined by a &lt;a class="wiki_link" href="/Normal%20lists"&gt;normal val list&lt;/a&gt; of r vals, or equivalently by an r-multival. The abstractly characterized intervals of the abstract temperament can then be mapped to a tuning; if the mapping is to a rank one tuning such as 31et, that does not affect the rank of the temperament.&lt;/body&gt;&lt;/html&gt;</pre></div>
Looking only at the number of independent generators of a tuning can obscure its real nature, at least as it is being applied. For instance, a 31et tuning of meantone temperament, with a meantone fifth of 18\31 octaves, is of rank one in the sense that all the intervals in the tuning are generated from 1\31; however, it is being used as a rank two tuning. This issue can be gotten around by means of &lt;a class="wiki_link_ext" href="http://et3allem.blogspot.com" rel="nofollow" target="_blank"&gt;abstract regular temperaments&lt;/a&gt;; an abstract regular temperament is of rank r if it is defined by a &lt;a class="wiki_link" href="/Normal%20lists"&gt;normal val list&lt;/a&gt; of r vals, or equivalently by an r-multival. The abstractly characterized intervals of the abstract temperament can then be mapped to a tuning; if the mapping is to a rank one tuning such as 31et, that does not affect the rank of the temperament.&lt;br /&gt;
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Revision as of 20:24, 31 October 2012

IMPORTED REVISION FROM WIKISPACES

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This revision was by author guest and made on 2012-10-31 20:24:48 UTC.
The original revision id was 378163648.
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Original Wikitext content:

The //rank// of a [[Regular Temperaments|regular temperament]] is the number of independent intervals, called //generators//, which can be combined together to obtain any interval of the temperament. For instance, every interval of [[meantone]] can be obtained as a combination of a certain number of octaves up or down, plus a certain number of flattened meantone fifths up or down. The terminology comes from group theory; in the parlance of group theory, the intervals of a regular temperament comprise a [[http://en.wikipedia.org/wiki/Free_abelian_group#Rank|finitely generated free abelian group]] with a rank equal to the number of generators.

The [[http://en.wikipedia.org/wiki/Codimension|codimension]] or [[http://en.wikipedia.org/wiki/Free_abelian_group#Rank|co-rank]] of a temperament is the number of [[Comma|commas]] needed to completely define the temperament. If the temperament tempers the [[Harmonic Limit|p-limit]] just intonation group generated by the first n primes, then if it tempers out n-r independent commas, it will be of rank r and codimension n-r. The terminology can also be applied to [[just intonation subgroups]]. In all cases care must be taken to specify the exact just intonation group which is being tempered by the tempering out of a set of commas.

Looking only at the number of independent generators of a tuning can obscure its real nature, at least as it is being applied. For instance, a 31et tuning of meantone temperament, with a meantone fifth of 18\31 octaves, is of rank one in the sense that all the intervals in the tuning are generated from 1\31; however, it is being used as a rank two tuning. This issue can be gotten around by means of [[@http://et3allem.blogspot.com|abstract regular temperaments]]; an abstract regular temperament is of rank r if it is defined by a [[Normal lists|normal val list]] of r vals, or equivalently by an r-multival. The abstractly characterized intervals of the abstract temperament can then be mapped to a tuning; if the mapping is to a rank one tuning such as 31et, that does not affect the rank of the temperament.

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Original HTML content:

<html><head><title>Rank and codimension</title></head><body>The <em>rank</em> of a <a class="wiki_link" href="/Regular%20Temperaments">regular temperament</a> is the number of independent intervals, called <em>generators</em>, which can be combined together to obtain any interval of the temperament. For instance, every interval of <a class="wiki_link" href="/meantone">meantone</a> can be obtained as a combination of a certain number of octaves up or down, plus a certain number of flattened meantone fifths up or down. The terminology comes from group theory; in the parlance of group theory, the intervals of a regular temperament comprise a <a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Free_abelian_group#Rank" rel="nofollow">finitely generated free abelian group</a> with a rank equal to the number of generators.<br />
<br />
The <a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Codimension" rel="nofollow">codimension</a> or <a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Free_abelian_group#Rank" rel="nofollow">co-rank</a> of a temperament is the number of <a class="wiki_link" href="/Comma">commas</a> needed to completely define the temperament. If the temperament tempers the <a class="wiki_link" href="/Harmonic%20Limit">p-limit</a> just intonation group generated by the first n primes, then if it tempers out n-r independent commas, it will be of rank r and codimension n-r. The terminology can also be applied to <a class="wiki_link" href="/just%20intonation%20subgroups">just intonation subgroups</a>. In all cases care must be taken to specify the exact just intonation group which is being tempered by the tempering out of a set of commas.<br />
<br />
Looking only at the number of independent generators of a tuning can obscure its real nature, at least as it is being applied. For instance, a 31et tuning of meantone temperament, with a meantone fifth of 18\31 octaves, is of rank one in the sense that all the intervals in the tuning are generated from 1\31; however, it is being used as a rank two tuning. This issue can be gotten around by means of <a class="wiki_link_ext" href="http://et3allem.blogspot.com" rel="nofollow" target="_blank">abstract regular temperaments</a>; an abstract regular temperament is of rank r if it is defined by a <a class="wiki_link" href="/Normal%20lists">normal val list</a> of r vals, or equivalently by an r-multival. The abstractly characterized intervals of the abstract temperament can then be mapped to a tuning; if the mapping is to a rank one tuning such as 31et, that does not affect the rank of the temperament.<br />
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