-<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
-<head>
- <meta content="text/html; charset=UTF-8" http-equiv="content-type">
- <title>lambda_delta home page</title>
- <meta content="Ferruccio Guidi" name="author">
- <meta content="The formal system lambda_delta" name="description">
- <link rel="shortcut icon" href="download/crux_16.ico">
-</head>
-<body>
-<div style="text-align: center;">
-<br>
-<a href="http://lambda-delta.info"><img alt="[Crux Logo]"
- title="The Crux" src="download/crux_32.png"
- style="border: 0px solid ; width: 32px; height: 32px;"></a>
-<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="download/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="download/b5.png"></h3>
- <ul>
- <li><span style="font-weight: bold;">December 2010.</span>
-Permanent λδ URL acquired: <a href="http://lambda-delta.info">http://lambda-delta.info</a>
-(pointing at this site). <br>
- <span style="font-weight: bold;"></span></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>
- </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>
- </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 </a><a
- href="implementation.html#helena">λδ</a><span
- style="font-style: italic;"></span>, <span style="font-style: italic;"></span>is
-available
-as a
-part of the <a href="http://helm.cs.unibo.it/">HELM</a> software. <br>
- </li>
- </ul>
- <span style="font-weight: bold;"></span>
- <ul>
- <li><span style="font-weight: bold;">September 2008.</span>
-This site is online.<br>
- </li>
- </ul>
- <span style="font-weight: bold;"></span>
- <ul>
- <li><span style="font-weight: bold;">July 2008.</span> <a
- href="documentation.html#tocl1">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> in <a href="http://matita.cs.unibo.it/">Matita 0.5</a>
-of the <a href="implementation.html#source">λδ proof scripts in
-Coq 7.3.1</a>.<br>
- </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 in Matita 0.5</a> are online.<br>
- <span style="font-weight: bold;"></span></li>
- </ul>
- <ul>
- <li><span style="font-weight: bold;">March 2008.</span> An
-improvement of the
-specification of λδ in Coq 7.3.1 begins:
- <ul>
+ <head>
+ <meta content="text/html; charset=UTF-8" http-equiv="content-type">
+ <title>lambda_delta home page</title>
+ <meta content="Ferruccio Guidi" name="author">
+ <meta content="The formal system lambda_delta" name="description">
+ <link rel="shortcut icon" href="download/crux_16.ico">
+ </head>
+ <body>
+ <div style="text-align: center;">
+ <br>
+ <a href="http://lambda-delta.info"><img alt="[Crux Logo]"
+ title="The Crux" src="download/crux_32.png" style="border: 0px
+ solid ; width: 32px; height: 32px;"></a>
+ <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="download/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="download/b5.png"></h3>
+ <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>
+ <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>
+ <li>The permanent λδ URL is sheduled to become <span
+ style="font-style: italic;">http://lambda_delta.info</span>
+ on
+ December 2012.<br>
+ </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>
+ </ul></li>
+ </ul>
+ <ul>
+ <li><span style="font-weight: bold;">December 2010.</span>
+ Permanent λδ URL acquired: <a
+ href="http://lambda-delta.info">http://lambda-delta.info</a>
+ (pointing at this site). <br>
+ <span style="font-weight: bold;"></span></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>
+ </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>
+ </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>
+ </ul>
+ <span style="font-weight: bold;"></span>
+ <ul>
+ <li><span style="font-weight: bold;">September 2008.</span>
+ This site is online.<br>
+ </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>
+ </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>
+ </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>
+ </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).
+ <!-- <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>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
<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>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
<li>we removed level indicators on environments (<span
style="font-style: italic;">cbk</span>).</li>
</ul>
- </li>
- </ul>
- <ul>
- <li><span style="font-weight: bold;">September 2007.</span>
-The <a href="implementation.html#dynamic">specification of λδ in
-Matita 0.4</a> is online.<br>
- </li>
- </ul>
- <ul>
- <li><span style="font-weight: bold;">December 2005.</span> <a
- href="documentation.html#bologna1">First communication on λδ</a>.<br>
- </li>
- </ul>
- <ul>
- <li><span style="font-weight: bold;">May 2004.</span> The <a
- href="implementation.html#source">specification of λδ in
-Coq 7.3.1</a> begins.<br>
- </li>
- </ul>
- <h3 style="text-align: right;">Visibility <img
- style="width: 37px; height: 37px;" alt="[Butterfly]" title="Butterfly"
- src="download/b4.png"></h3>
- <ul>
- <li><span style="font-weight: bold;">November 2010.</span> The <a
- href="http://www.google.com/">Google</a>
-search <span style="color: rgb(255, 0, 0);">formal system lambda delta</span>
-gives 8 resources about λδ as the first results.<br>
- </li>
- </ul>
- <ul>
- <li><span style="font-weight: bold;">November 2010.</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 and 2 sub-resources about λδ as the first 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"
- src="http://www.w3.org/Icons/valid-html401"
- style="border: 0px solid ; width: 88px; height: 31px;"></a> <a
- href="http://www.anybrowser.org/campaign/"><img
- alt="[Use Any Browser Here]" title="Use Any Browser Here"
- src="http://www.cs.unibo.it/%7Efguidi/download/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="http://www.cs.unibo.it/%7Efguidi/download/PNGnow2.png"><br>
-<br>
-Last update 2010-12-14 by <a href="http://www.cs.unibo.it/%7Efguidi/">Ferruccio
-Guidi</a><br>
-</div>
-</body>
+--> </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>
+ </ul>
+ <ul>
+ <li><span style="font-weight: bold;">November 2006.</span>
+ <a href="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>
+ </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>
+ </ul>
+ <h3 style="text-align: right;">Visibility <img
+ style="width: 37px; height: 37px;" alt="[Butterfly]"
+ title="Butterfly" src="download/b4.png"></h3>
+ <ul>
+ <li><span style="font-weight: bold;">February 2012.</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>
+ </ul>
+ <ul>
+ <li><span style="font-weight: bold;">February 2012.</span>
+ The <a href="http://www.yahoo.com/">Yahoo</a>
+ search <span style="color: rgb(255, 0, 0);">formal
+ system lambda delta</span>
+ gives this site as the first result.</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" src="http://www.w3.org/Icons/valid-html401"
+ style="border: 0px solid ; width: 88px; height: 31px;"></a> <a
+ href="http://www.anybrowser.org/campaign/"><img alt="[Use Any
+ Browser Here]" title="Use Any Browser Here"
+ src="download/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="download/PNGnow2.png"><br>
+ <br>
+ Last update 2012-04-16 by <a
+ href="http://www.cs.unibo.it/%7Efguidi/">Ferruccio
+ Guidi</a><br>
+ </div>
+ </body>
</html>