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- <meta content="Ferruccio Guidi" name="author">
- <meta content="The formal system λδ" name="description">
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-<h1>The Formal System λδ (\lambda\delta)<br>
-</h1>
-<h2>Towards the unification of terms, types, environments and contexts</h2>
-<img style="width: 95%; height: 4px;" alt="[Separator]"
- title="Separator" src="images/rainbow.png"><br>
-<table
- style="text-align: left; width: 95%; margin-left: auto; margin-right: auto;"
- border="0" cellpadding="2" cellspacing="20">
- <tbody>
- <tr>
- <td style="vertical-align: top;">
- <ul>
- <li><a href="index.html">Foreword</a></li>
- </ul>
- <ul>
- <li>News</li>
- </ul>
- <ul>
- <li><a href="documentation.html">Papers</a></li>
- </ul>
- <ul>
- <li><a href="implementation.html">Resources</a><br>
- </li>
- </ul>
- </td>
- <td style="vertical-align: top; text-align: left;">
- <h3 style="text-align: right;">News <img
- style="width: 37px; height: 37px;" alt="[Butterfly]" title="Butterfly"
- src="images/b5.png"></h3>
- <ul>
- <li><span style="font-weight: bold;">June 2014.</span> <a
- href="documentation.html#ldt8">First communication on λδ version 2.</a><br>
- <span style="font-weight: bold;"></span></li>
- </ul>
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+ </a>
+ </div>
+ <div class="head1">The Formal System λδ (\lambda\delta)</div>
+ <div class="spacer">
+ <img class="rule" alt="[Spacer]" title="lambdadelta rainbow rule" src="http://lambdadelta.info/images/rainbow.png" />
+ </div>
+ <div xmlns:ld="http://lambdadelta.info/" class="spacer">
+ <br />
+ </div>
+ <div xmlns:ld="http://lambdadelta.info/" class="text">
+ <table cellpadding="4" cellspacing="0">
+ <tbody>
+ <tr>
+ <td class="snns component sky">
+ <a href="http://lambdadelta.info/index.html">foreword</a>
+ </td>
+ <td class="snns component magenta">
+ <a href="http://lambdadelta.info/news.html">news</a>
+ </td>
+ <td class="snns component orange">
+ <a href="http://lambdadelta.info/documentation.html">documentation</a>
+ </td>
+ <td class="snns component green">
+ <a href="http://lambdadelta.info/implementation.html">implementation</a>
+ </td>
+ <td class="snnn component green">
+ <br />
+ </td>
+ <td class="snnn component green">
+ <br />
+ </td>
+ <td class="ssnn component green">
+ <br />
+ </td>
+ </tr>
+ <tr>
+ <td class="snns sky">
+ <br />
+ </td>
+ <td class="snns magenta">
+ <br />
+ </td>
+ <td class="snns orange">
+ <br />
+ </td>
+ <td class="snns green">
+ <a href="http://lambdadelta.info/version_2.html">Version 2</a>
+ </td>
+ <td class="snnn green">
+ <a href="http://lambdadelta.info/ground_2.html">Background</a>
+ </td>
+ <td class="snnn green">
+ <a href="http://lambdadelta.info/basic_2.html">Core</a>
+ </td>
+ <td class="ssnn green">
+ <a href="http://lambdadelta.info/apps_2.html">Applications</a>
+ </td>
+ </tr>
+ <tr>
+ <td class="nnss sky">
+ <br />
+ </td>
+ <td class="nnss magenta">
+ <br />
+ </td>
+ <td class="nnss orange">
+ <br />
+ </td>
+ <td class="snss green">
+ <a href="http://lambdadelta.info/version_1.html">Version 1</a>
+ </td>
+ <td class="snsn green">
+ <br />
+ </td>
+ <td class="snsn green">
+ <br />
+ </td>
+ <td class="sssn green">
+ <br />
+ </td>
+ </tr>
+ </tbody>
+ </table>
+ </div>
+
+ <div xmlns:ld="http://lambdadelta.info/" class="head2dx" id="milestones">Milestones <img class="icon37" alt="[spacer]" title="lambdadelta butterfly" src="http://lambdadelta.info/images/b5.png" />
+ </div>
+ <div xmlns:ld="http://lambdadelta.info/" class="text">
<ul>
- <li><span style="font-weight: bold;">December 2012.</span> The
-character "_" is removed from the denomination "lambda_delta". </li>
+ <li>
+ <span class="date">June 2014.</span>
+ <a href="http://lambdadelta.info/documentation.html#ldt8">First communication on λδ version 2.</a>
+ </li>
</ul>
<ul>
- <ul>
- <li>The denomination "\lambda\delta" is used in λδ-related
-texts.</li>
- <li>The denomination "lambdadelta" is used in λδ-related
-identifiers.</li>
- <li>Permanent λδ URL acquired: <a
- href="http://lambdadelta.info/">http://lambdadelta.info/</a>
-(pointing at this site). </li>
- </ul>
+ <li>
+ <span class="date">December 2012.</span>
+ The character "_" is removed from the denomination "lambda_delta":
+ <ul>
+ <li>
+ The denomination "\lambda\delta" is used in λδ-related texts.
+ </li>
+ <li>
+ The denomination "lambdadelta" is used in λδ-related identifiers.
+ </li>
+ <li>
+ Permanent λδ URL acquired:
+ <a href="http://lambdadelta.info/">http://lambdadelta.info/</a>
+ (pointing at this site).
+ </li>
+ </ul>
+ </li>
</ul>
<ul>
- <li><span style="font-weight: bold;">September 2011.</span> The
-denomination "lambda-delta" changes to "lambda_delta".
- <ul>
- <li>The character "-" is reserved in λδ textual syntax
-(recognized by <span style="font-style: italic;">Helena 0.8.1</span>).
+ <li>
+ <span class="date">September 2011.</span>
+ The denomination "lambda-delta" changes to "lambda_delta":
+ <ul>
+ <li>
+ The character "-" is reserved in λδ textual syntax
+ (recognized by "Helena 0.8.1").
</li>
- <li>Eventually, the occurrences of the character "-" will
-be replaced by "_" in all λδ-related identifiers.</li>
- <li>In particular, this refactoring involves file names and
-path names.</li>
- </ul>
- </li>
+ <li>
+ Eventually, the occurrences of the character "-"
+ will be replaced by "_" in all λδ-related identifiers.
+ </li>
+ <li>
+ In particular, this refactoring involves file names and path names.
+ </li>
+ </ul>
+ </li>
</ul>
<ul>
- <li><span style="font-weight: bold;">April 2011.</span> The
-specification of λδ version 2 and related topics is restarted in <a
- href="http://matita.cs.unibo.it/">Matita 0.5</a>.
- <ul>
- <li><a href="apps_2.html">Here</a> is a page about the
-topics related to the specification (Applications).</li>
- <li><a href="basic_2.html">Here</a> is a page about the
-specification (Core). </li>
- <li><a href="ground_2.html">Here</a> is a page about the
-background of the specification (Ground).</li>
- </ul>
- </li>
+ <li>
+ <span class="date">April 2011.</span>
+ The specification of <a href="http://lambdadelta.info/version_2.html">λδ version 2</a>
+ and related topics is restarted in
+ <a href="http://matita.cs.unibo.it/">Matita 0.5</a>.
+ </li>
</ul>
<ul>
- <li><span style="font-weight: bold;">December 2010.</span>
-Transient λδ URL acquired: http://lambda-delta.info/
-(expires on December 2012). <br>
- <span style="font-weight: bold;"></span></li>
+ <li>
+ <span class="date">December 2010.</span>
+ Transient λδ URL acquired: http://lambda-delta.info/ (expires on December 2012).
+ </li>
</ul>
<ul>
- <li><span style="font-weight: bold;">November 2010.</span> <span
- style="font-style: italic;">Helena 0.8.1</span> is released. <br>
- </li>
+ <li>
+ <span class="date">November 2010.</span>
+ "Helena 0.8.1" is released.
+ </li>
</ul>
<ul>
- <li><span style="font-weight: bold;">September 2009.</span> <span
- style="font-style: italic;">Helena 0.8.0</span> is released and the <a
- href="implementation.html#lddl">λδ Digital Library</a> is started.<br>
- <span style="font-weight: bold;"></span></li>
+ <li>
+ <span class="date">September 2009.</span>
+ "Helena 0.8.0" is released and the
+ <a href="http://lambdadelta.info/implementation.html#lddl">λδ Digital Library</a>
+ is started.
+ </li>
</ul>
<ul>
- <li><span style="font-weight: bold;">June 2009.</span> <span
- style="font-style: italic;">Helena</span>, a <a
- href="implementation.html#helena">validator for λδ version 2</a>, is
-available as a part of the <a href="http://helm.cs.unibo.it/">HELM</a>
-software. <br>
- </li>
+ <li>
+ <span class="date">June 2009.</span>
+ "Helena", a <a href="http://lambdadelta.info/implementation.html#helena">validator for λδ version 2</a>,
+ is available as a part of the <a href="http://helm.cs.unibo.it/">HELM</a> software.
+ </li>
</ul>
- <span style="font-weight: bold;"></span>
<ul>
- <li><span style="font-weight: bold;">September 2008.</span>
-This site is online.<br>
- </li>
+ <li>
+ <span class="date">September 2008.</span>
+ This site is online.
+ </li>
</ul>
- <span style="font-weight: bold;"></span>
<ul>
- <li><span style="font-weight: bold;">July 2008.</span> <a
- href="documentation.html#ldp5">First journal paper on λδ</a> accepted
-for publication.</li>
+ <li>
+ <span class="date">July 2008.</span>
+ <a href="http://lambdadelta.info/documentation.html#ldp5">First journal paper on λδ</a>
+ accepted for publication.
+ </li>
</ul>
<ul>
- <li><span style="font-weight: bold;">July 2008.</span> First <a
- href="http://helm.cs.unibo.it/procedural/">procedural reconstruction</a>
-for <a href="http://matita.cs.unibo.it/">Matita 0.5</a> of the <a
- href="implementation.html#ldp1">λδ proof scripts for Coq 7.3.1</a>.<br>
- </li>
+ <li>
+ <span class="date">July 2008.</span>
+ First <a href="http://helm.cs.unibo.it/procedural/">procedural reconstruction</a>
+ for <a href="http://matita.cs.unibo.it/">Matita 0.5</a>
+ of the λδ version 1 for Coq 7.3.1.
+ </li>
</ul>
<ul>
- <li><span style="font-weight: bold;">June 2008.</span> The <a
- href="implementation.html#static">HTML pages of the specification of
-λδ version 1 for Matita 0.5</a> are online.<br>
- <span style="font-weight: bold;"></span></li>
+ <li>
+ <span class="date">June 2008.</span>
+ The <a href="http://lambdadelta.info/version_1.html#static">
+ HTML pages of the specification of λδ version 1 for Matita 0.5</a>
+ are online.
+ </li>
</ul>
<ul>
- <li><span style="font-weight: bold;">May 2008.</span> The
-specification of λδ version 1 is dismissed.<br>
- <span style="font-weight: bold;"></span></li>
+ <li>
+ <span class="date">May 2008.</span>
+ The specification of λδ version 1 is dismissed.
+ </li>
</ul>
<ul>
- <li><span style="font-weight: bold;">March 2008.</span> The
-specification of λδ version 2 is started with Coq 7.3.1 (false start). </li>
+ <li>
+ <span class="date">March 2008.</span>
+ The specification of λδ version 2 is started with Coq 7.3.1 (false start).
+ </li>
</ul>
-<!-- <ul>
- <li>native type assignment with new rules for application: <span
- style="font-style: italic;">nty</span> (it replaces <span
- style="font-style: italic;">ty3</span>);<br>
- </li>
- <li>parallel conversion on focalized terms: <span
- style="font-style: italic;">fpcs</span> (it replaces <span
- style="font-style: italic;"></span><span style="font-style: italic;">pc3</span>);
- <br>
- </li>
- <li>new weak parallel reduction on environments: <span
- style="font-style: italic;">wcpr</span> <span
- style="font-style: italic;"></span>(it is based on <span
- style="font-style: italic;">fpr</span> and replaces <span
- style="font-style: italic;">wcpr0</span>); <br>
- </li>
- <li>parallel reduction on focalized terms: <span
- style="font-style: italic;">fpr</span> and <span
- style="font-style: italic;">fprs</span> (they replace <span
- style="font-style: italic;"></span><span style="font-style: italic;"></span><span
- style="font-style: italic;">pr2</span>, <span
- style="font-style: italic;">pr3</span>); <br>
- </li>
- </ul>
- <ul>
- <li>new thinning relation: <span
- style="font-style: italic;">drop</span>
-(it replaces the old <span style="font-style: italic;">drop</span>, <span
- style="font-style: italic;">clear</span>, <span
- style="font-style: italic;">getl</span>, <span
- style="font-style: italic;">cimp</span>, <span
- style="font-style: italic;">drop1</span>);</li>
- <li>new shift function: <span style="font-style: italic;">shift</span>:
-(it
-replaces
-
- <span style="font-style: italic;">app1</span>);</li>
- <li>new length function for environments: <span
- style="font-style: italic;">clen</span>;<br>
- </li>
- <li>new relocation function: <span
- style="font-style: italic;">lift</span> (it replaces old <span
- style="font-style: italic;">lift</span>, <span
- style="font-style: italic;">lift1</span>);<br>
- </li>
- <li>new term structure with polarity indicators and no
-distinction between binding and flat items;</li>
- <li>new general theory of relocation (comprises new
-relocation functions: <span style="font-style: italic;">s</span>, <span
- style="font-style: italic;">r</span>);</li>
- <li>we removed context-free reduction and conversion (<span
- style="font-style: italic;">pr0</span>, <span
- style="font-style: italic;">pr1</span>, <span
- style="font-style: italic;">pc1</span>);<br>
- </li>
- <li>we removed greedy substitution (<span
- style="font-style: italic;"></span><span style="font-style: italic;">csubst0</span>,
- <span style="font-style: italic;">csubst1</span>, <span
- style="font-style: italic;">fsubst0</span>, <span
- style="font-style: italic;">subst0</span>, <span
- style="font-style: italic;">subst1</span>);<br>
- </li>
- <li>we removed level indicators on environments (<span
- style="font-style: italic;">cbk</span>).</li>
- </ul>
--->
<ul>
- <li><span style="font-weight: bold;">September 2007.</span> The
- <a href="implementation.html#dynamic">specification of λδ
-version 1 for Matita 0.4</a> is online.</li>
+ <li>
+ <span class="date">September 2007.</span>
+ The <a href="http://lambdadelta.info/version_1.html#dynamic">
+ specification of λδ version 1 for Matita 0.4</a>
+ is online.
+ </li>
</ul>
<ul>
- <li><span style="font-weight: bold;">November 2006.</span> <a
- href="documentation.html#ldp3">λδ version 1</a> is released.</li>
+ <li>
+ <span class="date">November 2006.</span>
+ <a href="http://lambdadelta.info/documentation.html#ldp3">λδ version 1</a>
+ is released.
+ </li>
</ul>
<ul>
- <li><span style="font-weight: bold;">December 2005.</span> <a
- href="documentation.html#ldt1">First communication on λδ</a>.<br>
- </li>
+ <li>
+ <span class="date">December 2005.</span>
+ <a href="http://lambdadelta.info/documentation.html#ldt1">First communication on λδ</a>.
+ </li>
</ul>
<ul>
- <li><span style="font-weight: bold;">May 2004.</span> The <a
- href="implementation.html#ldp1">specification of λδ version 1</a> is
-started with Coq 7.3.1.<br>
- </li>
+ <li>
+ <span class="date">May 2004.</span>
+ The specification of <a href="http://lambdadelta.info/version_1.html">λδ version 1</a>
+ is started with Coq 7.3.1.
+ </li>
</ul>
- <h3 style="text-align: right;">Visibility <img
- style="width: 37px; height: 37px;" alt="[Butterfly]" title="Butterfly"
- src="images/b4.png"></h3>
+ </div>
+
+ <div xmlns:ld="http://lambdadelta.info/" class="head2dx" id="visibility">Visibility <img class="icon37" alt="[spacer]" title="lambdadelta butterfly" src="http://lambdadelta.info/images/b4.png" />
+ </div>
+ <div xmlns:ld="http://lambdadelta.info/" class="text">
<ul>
- <li><span style="font-weight: bold;">June 2014.</span> The <a
- href="http://www.google.com/">Google</a> search for <span
- style="color: rgb(255, 0, 0);">formal system lambda delta</span> gives
-5 resources about λδ in the first 6 results.<br>
- </li>
+ <li>
+ <span class="date">June 2014.</span>
+ The <a href="http://www.google.com/">Google</a>
+ search for "formal system lambda delta" gives
+ 5 resources about λδ in the first 6 results.
+ </li>
</ul>
<ul>
- <li><span style="font-weight: bold;">June 2014.</span> The <a
- href="http://www.yahoo.com/">Yahoo</a> search <span
- style="color: rgb(255, 0, 0);">formal system lambda delta</span> gives
-4 resources about λδ in the first 5 results.</li>
+ <li>
+ <span class="date">June 2014.</span>
+ The <a href="http://www.yahoo.com/">Yahoo</a>
+ search for "formal system lambda delta" gives
+ 4 resources about λδ in the first 5 results.
+ </li>
</ul>
- </td>
- </tr>
- </tbody>
-</table>
-<br>
-<a href="http://validator.w3.org/check?uri=referer"><img
- alt="[Valid HTML 4.01 Transitional]"
- title="Valid HTML 4.01
- Transitional"
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- href="http://www.anybrowser.org/campaign/"><img
- alt="[Use Any
- Browser Here]" title="Use Any Browser Here"
- src="images/globe_trans.png"
- style="border: 0px solid ; width: 147px; height: 42px;"></a> <img
- style="width: 88px; height: 31px;" alt="[PNG Used Here]"
- title="PNG Used Here" src="images/PNGnow2.png"><br>
-<br>
-Last update 2014-06-19 by <a href="http://www.cs.unibo.it/%7Efguidi/">Ferruccio
-Guidi</a><br>
-</div>
+ </div>
+
+ <div class="spacer">
+ <img class="rule" alt="[Spacer]" title="lambdadelta rainbow rule" src="http://lambdadelta.info/images/rainbow.png" />
+ </div>
+ <div xmlns:ld="http://lambdadelta.info/" class="spacer">
+ <br />
+ </div>
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+ <img class="w3c" alt="[Valid XHTML 1.1]" title="Valid XHTML 1.1" src="http://www.w3.org/Icons/valid-xhtml11-blue" />
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+ <img class="w3c" alt="[Valid CSS level 2]" title="Valid CSS level 2" src="http://www.w3.org/Icons/valid-css2-blue" />
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+ <img class="w3c" alt="[Generated from XML via XSL]" title="Generated from XML via XSL" src="http://lambdadelta.info/images/xml_xsl2.png" />
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+ <img class="w3c" alt="[PNG used here]" title="PNG used here" src="http://lambdadelta.info/images/PNGnow2.png" />
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+ <img class="w3c" alt="[Viewable with any browser]" title="Viewable with any browser" src="http://www.anybrowser.org/campaign/bvgraphics/abtfile.png" />
+ </a>
+ </div>
+ <div xmlns:ld="http://lambdadelta.info/" class="spacer">
+ <br />
+ </div>
+ <div xmlns:ld="http://lambdadelta.info/" class="spacer">Last update: Sun, 13 Jul 2014 15:59:00 +0200</div>
</body>
</html>
--- /dev/null
+<?xml version="1.0" encoding="UTF-8"?>
+
+<page xmlns="http://lambdadelta.info/"
+ description = "\lambda\delta home page"
+ title = "\lambda\delta home page"
+ head = "The Formal System λδ (\lambda\delta)"
+>
+ <sitemap name="sitemap"/>
+
+ <section5 name="milestones">Milestones</section5>
+ <body>
+ <news date="June 2014.">
+ <rlink to="documentation.html#ldt8">First communication on λδ version 2.</rlink>
+ </news>
+ <news date="December 2012.">
+ The character "_" is removed from the denomination "lambda_delta":
+ <list>
+ <item>
+ The denomination "\lambda\delta" is used in λδ-related texts.
+ </item>
+ <item>
+ The denomination "lambdadelta" is used in λδ-related identifiers.
+ </item>
+ <item>
+ Permanent λδ URL acquired:
+ <rlink to="">http://lambdadelta.info/</rlink>
+ (pointing at this site).
+ </item>
+ </list>
+ </news>
+ <news date="September 2011.">
+ The denomination "lambda-delta" changes to "lambda_delta":
+ <list>
+ <item>
+ The character "-" is reserved in λδ textual syntax
+ (recognized by "Helena 0.8.1").
+ </item>
+ <item>
+ Eventually, the occurrences of the character "-"
+ will be replaced by "_" in all λδ-related identifiers.
+ </item>
+ <item>
+ In particular, this refactoring involves file names and path names.
+ </item>
+ </list>
+ </news>
+ <news date="April 2011.">
+ The specification of <rlink to="version_2.html">λδ version 2</rlink>
+ and related topics is restarted in
+ <link to="http://matita.cs.unibo.it/">Matita 0.5</link>.
+ </news>
+ <news date="December 2010.">
+ Transient λδ URL acquired: http://lambda-delta.info/ (expires on December 2012).
+ </news>
+ <news date="November 2010.">
+ "Helena 0.8.1" is released.
+ </news>
+ <news date="September 2009.">
+ "Helena 0.8.0" is released and the
+ <rlink to="implementation.html#lddl">λδ Digital Library</rlink>
+ is started.
+ </news>
+ <news date="June 2009.">
+ "Helena", a <rlink to="implementation.html#helena">validator for λδ version 2</rlink>,
+ is available as a part of the <link to="http://helm.cs.unibo.it/">HELM</link> software.
+ </news>
+ <news date="September 2008.">
+ This site is online.
+ </news>
+ <news date="July 2008.">
+ <rlink to="documentation.html#ldp5">First journal paper on λδ</rlink>
+ accepted for publication.
+ </news>
+ <news date="July 2008.">
+ First <link to="http://helm.cs.unibo.it/procedural/">procedural reconstruction</link>
+ for <link to="http://matita.cs.unibo.it/">Matita 0.5</link>
+ of the λδ version 1 for Coq 7.3.1.
+ </news>
+ <news date="June 2008.">
+ The <rlink to="version_1.html#static">
+ HTML pages of the specification of λδ version 1 for Matita 0.5</rlink>
+ are online.
+ </news>
+ <news date="May 2008.">
+ The specification of λδ version 1 is dismissed.
+ </news>
+ <news date="March 2008.">
+ The specification of λδ version 2 is started with Coq 7.3.1 (false start).
+ </news>
+ <news date="September 2007.">
+ The <rlink to="version_1.html#dynamic">
+ specification of λδ version 1 for Matita 0.4</rlink>
+ is online.
+ </news>
+ <news date="November 2006.">
+ <rlink to="documentation.html#ldp3">λδ version 1</rlink>
+ is released.
+ </news>
+ <news date="December 2005.">
+ <rlink to="documentation.html#ldt1">First communication on λδ</rlink>.
+ </news>
+ <news date="May 2004.">
+ The specification of <rlink to="version_1.html">λδ version 1</rlink>
+ is started with Coq 7.3.1.
+ </news>
+ </body>
+
+ <section4 name="visibility">Visibility</section4>
+ <body>
+ <news date="June 2014.">
+ The <link to="http://www.google.com/">Google</link>
+ search for "formal system lambda delta" gives
+ 5 resources about λδ in the first 6 results.
+ </news>
+ <news date="June 2014.">
+ The <link to="http://www.yahoo.com/">Yahoo</link>
+ search for "formal system lambda delta" gives
+ 4 resources about λδ in the first 5 results.
+ </news>
+ </body>
+
+ <footer/>
+</page>
projects / helm.git / commitdiff