+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
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+ <head>
+ <meta http-equiv="Content-Language" content="en-us" />
+ <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
+ <meta http-equiv="Content-Style-Type" content="text/css" />
+ <meta name="author" content="Ferruccio Guidi" />
+ <meta name="description" content="\lambda\delta home page" />
+ <title>\lambda\delta home page</title>
+ <link rel="stylesheet" type="text/css" href="http://lambdadelta.info/css/ld_web.css" />
+ <link rel="stylesheet" type="text/css" href="http://lambdadelta.info/css/lddl.css" />
+ <link rel="stylesheet" type="text/css" href="http://lambdadelta.info/css/xhtbl.css" />
+ <link rel="shortcut icon" href="http://lambdadelta.info/images/crux_16.ico" />
+ </head>
+ <body lang="en-US">
+ <div class="spacer">
+ <a href="http://lambdadelta.info/">
+ <img class="icon32" alt="[lambdadelta home]" title="lambdadelta home" src="http://lambdadelta.info/images/crux_32.png" />
+ </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 capitalize italic sky">
+ <a href="http://lambdadelta.info/index.html">home</a>
+ </td>
+ <td class="snns capitalize italic magenta">
+ <a href="http://lambdadelta.info/news.html">news</a>
+ </td>
+ <td class="snns capitalize italic orange">
+ <a href="http://lambdadelta.info/documentation.html">documentation</a>
+ </td>
+ <td class="snns capitalize italic green">
+ <a href="http://lambdadelta.info/specification.html">specification</a>
+ </td>
+ <td class="snnn capitalize italic green">
+ <br />
+ </td>
+ <td class="ssns capitalize italic green">
+ <a href="http://lambdadelta.info/implementation.html">implementation</a>
+ </td>
+ </tr>
+ <tr>
+ <td class="snns capitalize sky">
+ <a href="http://lambdadelta.info/index.html#foreword">foreword</a>
+ </td>
+ <td class="snns capitalize magenta">
+ <a href="http://lambdadelta.info/news.html#milestones">milestones</a>
+ </td>
+ <td class="snns capitalize orange">
+ <a href="http://lambdadelta.info/documentation.html#v2">version 2</a>
+ </td>
+ <td class="snns capitalize green">
+ <a href="http://lambdadelta.info/specification.html#v2">version 2</a>
+ </td>
+ <td class="snnn capitalize green">(<a href="http://lambdadelta.info/ground_2.html">background</a> - <a href="http://lambdadelta.info/basic_2.html">core</a> - <a href="http://lambdadelta.info/apps_2.html">applications</a>)</td>
+ <td class="ssns capitalize green">
+ <a href="http://lambdadelta.info/implementation.html#lddl">library</a>
+ </td>
+ </tr>
+ <tr>
+ <td class="snss capitalize sky">
+ <a href="http://lambdadelta.info/index.html#notice">notice</a>
+ </td>
+ <td class="snss capitalize magenta">
+ <a href="http://lambdadelta.info/news.html#visibility">visibility</a>
+ </td>
+ <td class="snss capitalize orange">
+ <a href="http://lambdadelta.info/documentation.html#v1">version 1</a>
+ </td>
+ <td class="snss capitalize green">
+ <a href="http://lambdadelta.info/specification.html#v1">version 1</a>
+ </td>
+ <td class="snsn capitalize green">
+ <br />
+ </td>
+ <td class="ssss capitalize green">
+ <a href="http://lambdadelta.info/implementation.html#helena">helena</a>
+ </td>
+ </tr>
+ </tbody>
+ </table>
+ </div>
+
+ <div xmlns:ld="http://lambdadelta.info/" class="head2dx" id="specifications">Computer-checked formal specifications <img class="icon37" alt="[spacer]" title="lambdadelta butterfly" src="http://lambdadelta.info/images/b5.png" />
+ </div>
+ <div xmlns:ld="http://lambdadelta.info/" class="text">
+ λδ is developed as a machine-checked digital specification.
+ It comes in several versions listed in the next table,
+ which includes the major milestones:
+ </div>
+ <div xmlns:ld="http://lambdadelta.info/" class="text">
+ <table cellpadding="4" cellspacing="0">
+ <tbody>
+ <tr>
+ <td class="snns top capitalize italic gray">version</td>
+ <td class="snnn top capitalize italic gray">name</td>
+ <td class="snnn top capitalize italic gray">developed with</td>
+ <td class="snnn top capitalize italic gray">stage</td>
+ <td class="snnn top capitalize italic gray">started</td>
+ <td class="snnn top capitalize italic gray">announced</td>
+ <td class="snnn top capitalize italic gray">released</td>
+ <td class="ssnn top capitalize italic gray">dismissed</td>
+ </tr>
+ <tr>
+ <td class="snns top orange">
+ <a href="http://lambdadelta.info/specification.html#v2">Version 2</a>
+ </td>
+ <td class="snnn top orange">"basic_2"</td>
+ <td class="snnn top orange">
+ <a href="http://matita.cs.unibo.it/">Matita 0.99.2</a>
+ </td>
+ <td class="snnn top orange">"A"</td>
+ <td class="snnn top orange">April 2011</td>
+ <td class="snnn top orange">June 2014</td>
+ <td class="snnn top orange">Planned in October 2014</td>
+ <td class="ssnn top orange">Not planned yet</td>
+ </tr>
+ <tr>
+ <td class="snss top red">
+ <a href="http://lambdadelta.info/specification.html#v1">Version 1</a>
+ </td>
+ <td class="snsn top red">"basic_1"</td>
+ <td class="snsn top red">
+ <a href="http://coq.inria.fr/">Coq 7.3.1</a>
+ </td>
+ <td class="snsn top red" />
+ <td class="snsn top red">May 2004</td>
+ <td class="snsn top red">December 2005</td>
+ <td class="snsn top red">November 2006</td>
+ <td class="sssn top red">May 2008</td>
+ </tr>
+ </tbody>
+ </table>
+ </div>
+
+
+
+ <div xmlns:ld="http://lambdadelta.info/" class="head3sn" id="v2">
+ <img class="icon37" alt="[spacer]" title="lambdadelta butterfly" src="http://lambdadelta.info/images/b4.png" /> λδ version 2 (in progress)</div>
+ <div xmlns:ld="http://lambdadelta.info/" class="text">
+ The formal specification of λδ version 2
+ is available in the following formats:
+ </div>
+
+ <ul xmlns:ld="http://lambdadelta.info/" id="source2">
+ <li>
+ <a href="http://lambdadelta.info/download/lambdadelta_2.tar.gz">lambdadelta_2 for Matita 0.99.2</a>
+ (revised <span class="date">2014-10</span>).
+ Source scripts.
+ </li>
+ </ul>
+
+ <div xmlns:ld="http://lambdadelta.info/" class="text">
+ Informational pages on the parts of the specification:
+ <a href="http://lambdadelta.info/ground_2.html">Background</a>,
+ <a href="http://lambdadelta.info/basic_2.html">Core</a>,
+ <a href="http://lambdadelta.info/apps_2.html">Applications</a>.
+ </div>
+
+
+
+ <div xmlns:ld="http://lambdadelta.info/" class="head3sn" id="v1">
+ <img class="icon37" alt="[spacer]" title="lambdadelta butterfly" src="http://lambdadelta.info/images/b6.png" /> λδ version 1 (dismissed)</div>
+ <div xmlns:ld="http://lambdadelta.info/" class="text">
+ The formal specification of λδ version 1
+ is available in the following formats:
+ </div>
+
+ <ul xmlns:ld="http://lambdadelta.info/" id="source1">
+ <li>
+ <a href="http://lambdadelta.info/download/lambdadelta_1.tar.gz">lambdadelta_1 for Coq 7.3.1</a>
+ (revised <span class="date">2012-10</span>).
+ Source scripts.
+ </li>
+ </ul>
+
+ <ul xmlns:ld="http://lambdadelta.info/" id="static1">
+ <li>
+ <a href="http://lambdadelta.info/static/matita/lambdadelta/">lambdadelta_1 for Matita 0.5"</a>
+ (revised <span class="date">2011-09</span>).
+ Static HTML pages generated by the <a href="http://helm.cs.unibo.it/">HELM</a> rendering engine.
+ <ul>
+ <li>
+ <a href="http://lambdadelta.info/static/matita/lambdadelta/basic_1/pr3/pr3/pr3_confluence.con.html">
+ Confluence of reduction</a>
+ (Church-Rosser property).
+ </li>
+ <li>
+ <a href="http://lambdadelta.info/static/matita/lambdadelta/basic_1/ty3/props/ty3_correct.con.html">
+ Correctness of types</a>.
+ </li>
+ <li>
+ <a href="http://lambdadelta.info/static/matita/lambdadelta/basic_1/ty3/props/ty3_unique.con.html">
+ Uniqueness of types up to conversion</a>.
+ </li>
+ <li>
+ <a href="http://lambdadelta.info/static/matita/lambdadelta/basic_1/ty3/pr3/ty3_sred_pr3.con.html">
+ Subject reduction of the type assignment</a>.
+ </li>
+ <li>
+ <a href="http://lambdadelta.info/static/matita/lambdadelta/basic_1/ty3/arity_props/ty3_sn3.con.html">
+ Strong normalization of the typed terms</a>.
+ </li>
+ <li>
+ <a href="http://lambdadelta.info/static/matita/lambdadelta/basic_1/ty3/dec/ty3_inference.con.html">
+ Decidability of the type inference problem</a>.
+ </li>
+ </ul>
+ </li>
+ </ul>
+
+ <ul xmlns:ld="http://lambdadelta.info/" id="dynamic1">
+ <li>
+ <a href="http://mowgli.cs.unibo.it:58080/apply?keys=RT&xmluri=http://helm.cs.unibo.it/helm//html/folder/index.html&prop.media-type=text/html&param.thmedia-type=text/html&param.thkeys=T1%2CT2%2CL%2CE&param.embedkeys=d_c%2CTC1%2CHC2%2CL&param.thencoding=UTF-8&prop.encoding=UTF-8&prop.doctype-public=-//W3C//DTD%20XHTML%201.0%20Transitional//EN&param.doctype-public=-//W3C//DTD%20XHTML%201.0%20Transitional//EN&param.encoding=UTF-8&param.media-type=text/html&param.keys=d_c%2CC1%2CHC2%2CL&profile=default&param.profile=default&param.CICURI=theory:/matita/lambdadelta/">
+ lambdadelta_1 for Matita 0.5"</a>
+ (revised <span class="date">2011-09</span>).
+ <a href="http://helm.cs.unibo.it/">HELM</a> directory.
+ <span class="date">Notice: the HELM rendering engine is offline.</span>
+ </li>
+ </ul>
+
+ <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="spacer">
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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" />
+ </a>
+ <a href="http://www.w3.org/Graphics/PNG/">
+ <img class="w3c" alt="[PNG used here]" title="PNG used here" src="http://lambdadelta.info/images/PNGnow2.png" />
+ </a>
+ <a href="http://www.anybrowser.org/campaign/">
+ <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: Thu, 09 Oct 2014 16:26:23 +0200</div>
+</body>
+</html>