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    <title>Tom Moertel's Weblog: Perl helps prove universality of 2, 3 Turing machine</title>
    <link>http://blog.moertel.com/articles/2007/10/26/perl-helps-prove-universality-of-2-3-turing-machine</link>
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      <title>Perl helps prove universality of 2, 3 Turing machine</title>
      <description>&lt;p&gt;Alex Smith, a 20-year-old EE student in the UK, &lt;a href="http://www.nature.com/news/2007/071024/full/news.2007.190.html"&gt;proved that the 2, 3 Turing machine is universal&lt;/a&gt;. In doing so, he was able to claim the $25,000 prize that Stephen Wolfram offered for the first proof (or disproof) of the 2, 3 machine&amp;#8217;s universality.&lt;/p&gt;


	&lt;p&gt;This story has been getting a lot of attention lately, but one part of
the story has not: that the &lt;strong&gt;Perl&lt;/strong&gt; programming language is featured in the proof. In his documentation of the proof, &lt;a href="http://www.wolframscience.com/prizes/tm23/TM23Proof.pdf"&gt;Universality of Wolfram’s 2, 3 Turing
Machine&lt;/a&gt;,
Smith wrote, &amp;#8220;I have written several Perl programs, to demonstrate the
constructions given in the proof and to interpret the systems given in
various conjectures.&amp;#8221;  Smith&amp;#8217;s proof includes no fewer than 7 Perl
programs.&lt;/p&gt;


	&lt;p&gt;Go Perl!&lt;/p&gt;</description>
      <pubDate>Fri, 26 Oct 2007 13:23:00 -0400</pubDate>
      <guid isPermaLink="false">urn:uuid:bc3fe548-c24c-46bc-9c90-bba00f0326e9</guid>
      <author>Tom Moertel</author>
      <link>http://blog.moertel.com/articles/2007/10/26/perl-helps-prove-universality-of-2-3-turing-machine</link>
      <category>perl</category>
      <category>perl</category>
      <category>math</category>
      <category>proof</category>
      <trackback:ping>http://blog.moertel.com/articles/trackback/607</trackback:ping>
    </item>
    <item>
      <title>"Perl helps prove universality of 2, 3 Turing machine" by Ken Williams</title>
      <description>&lt;p&gt;I think the validity of the proof is currently under debate.  See:&lt;/p&gt;


	&lt;pre&gt;&lt;code&gt;&lt;a href="http://science.slashdot.org/article.pl?sid=07/10/29/2212226"&gt;http://science.slashdot.org/article.pl?sid=07/10/29/2212226&lt;/a&gt;&lt;/code&gt;&lt;/pre&gt;


	&lt;p&gt;I don&amp;#8217;t know what progress toward resolution has been made since then, though.&lt;/p&gt;</description>
      <pubDate>Thu, 01 Nov 2007 18:35:48 -0400</pubDate>
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      <link>http://blog.moertel.com/articles/2007/10/26/perl-helps-prove-universality-of-2-3-turing-machine#comment-615</link>
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