Tp tuning: Difference between revisions
Wikispaces>genewardsmith **Imported revision 354219176 - Original comment: ** |
Wikispaces>clumma **Imported revision 354228342 - Original comment: ** |
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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> | This is an imported revision from Wikispaces. The revision metadata is included below for reference:<br> | ||
: This revision was by author [[User: | : This revision was by author [[User:clumma|clumma]] and made on <tt>2012-07-21 16:47:21 UTC</tt>.<br> | ||
: The original revision id was <tt> | : The original revision id was <tt>354228342</tt>.<br> | ||
: The revision comment was: <tt></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> | The revision contents are below, presented both in the original Wikispaces Wikitext format, and in HTML exactly as Wikispaces rendered it.<br> | ||
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=Applying the Hahn-Banach theorem= | =Applying the Hahn-Banach theorem= | ||
Suppose T = Lp(S) is | Suppose T = Lp(S) is an Lp tuning for the temperament S, and J is the JI tuning. These are both elements of G-tuning space, which are linear functionals on G-interval space, and hence the error map Ɛ = T - J is also. The norm ||Ɛ|| of Ɛ is minimal among all error maps for tunings since T is the Lp tuning. By the [[http://en.wikipedia.org/wiki/Hahn%E2%80%93Banach_theorem|Hahn–Banach theorem]], Ɛ can be extended to an element Ƹ of the full p-limit tuning space with the same norm; that is, so that ||Ɛ|| = ||Ƹ||. This norm must be minimal for the whole tuning space, or the restriction of Ƹ to G would improve on Ɛ. Hence, Ƹ must be the tuning for the full p-limit for the same group of null elements c generated by the commas S. Thus to find the Lp tuning for the group G, we may first find the tuning for the corresponding higher-rank temperament for the full p-limit group, and then apply it to the normal interval list giving the standard form of generators for G. | ||
=L2 tuning= | =L2 tuning= | ||
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<!-- ws:start:WikiTextHeadingRule:6:&lt;h1&gt; --><h1 id="toc2"><a name="Applying the Hahn-Banach theorem"></a><!-- ws:end:WikiTextHeadingRule:6 -->Applying the Hahn-Banach theorem</h1> | <!-- ws:start:WikiTextHeadingRule:6:&lt;h1&gt; --><h1 id="toc2"><a name="Applying the Hahn-Banach theorem"></a><!-- ws:end:WikiTextHeadingRule:6 -->Applying the Hahn-Banach theorem</h1> | ||
Suppose T = Lp(S) is | Suppose T = Lp(S) is an Lp tuning for the temperament S, and J is the JI tuning. These are both elements of G-tuning space, which are linear functionals on G-interval space, and hence the error map Ɛ = T - J is also. The norm ||Ɛ|| of Ɛ is minimal among all error maps for tunings since T is the Lp tuning. By the <a class="wiki_link_ext" href="http://en.wikipedia.org/wiki/Hahn%E2%80%93Banach_theorem" rel="nofollow">Hahn–Banach theorem</a>, Ɛ can be extended to an element Ƹ of the full p-limit tuning space with the same norm; that is, so that ||Ɛ|| = ||Ƹ||. This norm must be minimal for the whole tuning space, or the restriction of Ƹ to G would improve on Ɛ. Hence, Ƹ must be the tuning for the full p-limit for the same group of null elements c generated by the commas S. Thus to find the Lp tuning for the group G, we may first find the tuning for the corresponding higher-rank temperament for the full p-limit group, and then apply it to the normal interval list giving the standard form of generators for G.<br /> | ||
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<!-- ws:start:WikiTextHeadingRule:8:&lt;h1&gt; --><h1 id="toc3"><a name="L2 tuning"></a><!-- ws:end:WikiTextHeadingRule:8 -->L2 tuning</h1> | <!-- ws:start:WikiTextHeadingRule:8:&lt;h1&gt; --><h1 id="toc3"><a name="L2 tuning"></a><!-- ws:end:WikiTextHeadingRule:8 -->L2 tuning</h1> |