Eigenmonzo basis: Difference between revisions

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<h2>IMPORTED REVISION FROM WIKISPACES</h2>
An [[eigenmonzo|eigenmonzo or unchanged-interval]] is a rational interval tuned justly by a [[regular temperament]] tuning. In other words, if a tuning is ''T'', then an eigenmonzo ''q'' satisfies {{nowrap| ''T''(''q'') {{=}} ''q'' }}. The eigenmonzos of ''T'' define a [[just intonation subgroup]], the eigenmonzo subgroup, whose basis is an '''eigenmonzo basis''' or '''unchanged-interval basis'''.
This is an imported revision from Wikispaces. The revision metadata is included below for reference:<br>
: This revision was by author [[User:genewardsmith|genewardsmith]] and made on <tt>2011-05-19 16:17:16 UTC</tt>.<br>
: The original revision id was <tt>230118236</tt>.<br>
: The revision comment was: <tt></tt><br>
The revision contents are below, presented both in the original Wikispaces Wikitext format, and in HTML exactly as Wikispaces rendered it.<br>
<h4>Original Wikitext 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;white-space: pre-wrap ! important" class="old-revision-html">Given a [[Abstract regular temperament|regular temperament]] tuning T, an [[Fractional monzos|eigenmonzo]] is a rational interval q such that T(q) = q; that is, T tunes q justly. The eigenmonzos of T define a [[Just intonation subgroups|just intonation subgoup]], the eigenmonzo subgroup.


One sort of example is provided by any equal division of the octave, where 2 (the octave) is always an eigenmonzo and the group {2^n} of powers of 2 is the eigenmonzo subgroup. The idea is most useful in connection to the [[Target tunings|minimax tunings]] of regular temperaments, where for a rank r regular temperament, the eigenmonzo subgroup is a rank r JI subgroup whose generators, together with generators for the commas of the subgroup, can be used to define the [[Target tunings|projection map]] of the minimax tuning and hence define the tuning.</pre></div>
One sort of example is provided by any equal division of the octave, where 2 (the octave) is always an eigenmonzo and the group {2<sup>''n''</sup>} of powers of 2 is the eigenmonzo subgroup.  
<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;Eigenmonzo subgroup&lt;/title&gt;&lt;/head&gt;&lt;body&gt;Given a &lt;a class="wiki_link" href="/Abstract%20regular%20temperament"&gt;regular temperament&lt;/a&gt; tuning T, an &lt;a class="wiki_link" href="/Fractional%20monzos"&gt;eigenmonzo&lt;/a&gt; is a rational interval q such that T(q) = q; that is, T tunes q justly. The eigenmonzos of T define a &lt;a class="wiki_link" href="/Just%20intonation%20subgroups"&gt;just intonation subgoup&lt;/a&gt;, the eigenmonzo subgroup.&lt;br /&gt;
The idea is most useful in connection to the [[Target tuning #Minimax tuning|minimax tunings]] of regular temperaments, where for a rank-''r'' regular temperament, the eigenmonzo subgroup is a rank-''r'' JI subgroup whose generators, together with generators for the commas of the subgroup, can be used to define the [[projection matrix]] of the minimax tuning and hence define the tuning.
&lt;br /&gt;
 
One sort of example is provided by any equal division of the octave, where 2 (the octave) is always an eigenmonzo and the group {2^n} of powers of 2 is the eigenmonzo subgroup. The idea is most useful in connection to the &lt;a class="wiki_link" href="/Target%20tunings"&gt;minimax tunings&lt;/a&gt; of regular temperaments, where for a rank r regular temperament, the eigenmonzo subgroup is a rank r JI subgroup whose generators, together with generators for the commas of the subgroup, can be used to define the &lt;a class="wiki_link" href="/Target%20tunings"&gt;projection map&lt;/a&gt; of the minimax tuning and hence define the tuning.&lt;/body&gt;&lt;/html&gt;</pre></div>
== See also ==
* [[Projection #The unchanged-interval basis]], for a discussion of this concept in the context of other related temperament tuning objects
 
[[Category:Regular temperament theory]]
[[Category:Terms]]
[[Category:Math]]
[[Category:Monzo]]