helm/www/lambdadelta/news.html

   1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
   2 <html dir="ltr" lang="en-us"><head>
   3
   4
   5   <meta content="text/html; charset=UTF-8" http-equiv="content-type"><title>λδ home page</title>
   6
   7   <meta content="Ferruccio Guidi" name="author">
   8   <meta content="The formal system λδ" name="description">
   9   <link rel="shortcut icon" href="images/crux_16.ico"></head><body>
  10 <div style="text-align: center;"> <br>
  11 <a href="http://lambdadelta.info"><img alt="[Crux Logo]" title="The Crux" src="images/crux_32.png" style="border: 0px solid ; width: 32px; height: 32px;"></a>
  12 <h1>The Formal System λδ (\lambda\delta)<br>
  13 </h1>
  14 <h2>Towards the unification of terms, types, environments and contexts</h2>
  15 <img style="width: 95%; height: 4px;" alt="[Separator]" title="Separator" src="images/rainbow.png"><br>
  16 <table style="text-align: left; width: 95%; margin-left: auto; margin-right: auto;" border="0" cellpadding="2" cellspacing="20">
  17   <tbody>
  18     <tr>
  19       <td style="vertical-align: top;">
  20       <ul>
  21         <li><a href="index.html">Foreword</a></li>
  22       </ul>
  23       <ul>
  24         <li>News</li>
  25       </ul>
  26       <ul>
  27         <li><a href="documentation.html">Papers</a></li>
  28       </ul>
  29       <ul>
  30         <li><a href="implementation.html">Resources</a><br>
  31         </li>
  32       </ul>
  33       </td>
  34       <td style="vertical-align: top; text-align: left;">
  35       <h3 style="text-align: right;">News <img style="width: 37px; height: 37px;" alt="[Butterfly]" title="Butterfly" src="images/b5.png"></h3>
  36       <ul>
  37
  38         <li><span style="font-weight: bold;">December 2012.</span> The character "_" is removed from the denomination "lambda_delta". <br>
  39         </li>
  40         <ul>
  41           <li>The denomination "\lambda\delta" is used in λδ-related texts.</li>
  42           <li>The denomination "lambdadelta" is used in λδ-related identifiers.</li>
  43           <li>Permanent λδ URL acquired: <a href="http://lambdadelta.info/">http://lambdadelta.info/</a>
  44 (pointing at this site). </li>
  45         </ul>
  46 </ul>
  47       <ul>
  48         <li><span style="font-weight: bold;">September 2011.</span> The
  49 denomination "lambda-delta" changes to "lambda_delta".
  50           <ul>
  51             <li>The character "-" is reserved in λδ textual syntax
  52 (recognized by <span style="font-style: italic;">Helena 0.8.1</span>).
  53             </li>
  54             <li>Eventually, the occurrences of the character "-" will
  55 be replaced by "_" in all λδ-related identifiers.</li>
  56             <li>In particular, this refactoring involves file names and
  57 path names.</li>
  58
  59           </ul>
  60         </li>
  61
  62
  63       </ul>
  64
  65       <ul>
  66         <li><span style="font-weight: bold;">April 2011.</span> The
  67 specification of λδ version 2 and related topics is restarted in <a href="http://matita.cs.unibo.it/">Matita 0.5</a>.
  68           <ul>
  69             <li><a href="apps_2.html">Here</a> is a page about the
  70 topics related to the specification (Applications).</li>
  71             <li><a href="basic_2.html">Here</a> is a page about the
  72 specification (Core). </li>
  73           </ul>
  74         </li>
  75       </ul>
  76       <ul>
  77         <li><span style="font-weight: bold;">December 2010.</span> Transient λδ URL acquired: http://lambda-delta.info/
  78 (expires on December 2012). <br>
  79           <span style="font-weight: bold;"></span></li>
  80       </ul>
  81       <ul>
  82         <li><span style="font-weight: bold;">November 2010.</span> <span style="font-style: italic;">Helena 0.8.1</span> is released. <br>
  83         </li>
  84       </ul>
  85       <ul>
  86         <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>
  87           <span style="font-weight: bold;"></span></li>
  88       </ul>
  89       <ul>
  90         <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
  91 available as a part of the <a href="http://helm.cs.unibo.it/">HELM</a>
  92 software. <br>
  93         </li>
  94       </ul>
  95       <span style="font-weight: bold;"></span>
  96       <ul>
  97         <li><span style="font-weight: bold;">September 2008.</span>
  98 This site is online.<br>
  99         </li>
 100       </ul>
 101       <span style="font-weight: bold;"></span>
 102       <ul>
 103         <li><span style="font-weight: bold;">July 2008.</span> <a href="documentation.html#ldp5">First journal paper on λδ</a> accepted
 104 for publication.</li>
 105       </ul>
 106       <ul>
 107         <li><span style="font-weight: bold;">July 2008.</span> First <a href="http://helm.cs.unibo.it/procedural/">procedural reconstruction</a>
 108 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>
 109         </li>
 110       </ul>
 111       <ul>
 112         <li><span style="font-weight: bold;">June 2008.</span> The <a href="implementation.html#static">HTML pages of the specification of
 113 λδ version 1 for Matita 0.5</a> are online.<br>
 114           <span style="font-weight: bold;"></span></li>
 115       </ul>
 116       <ul>
 117         <li><span style="font-weight: bold;">May 2008.</span> The
 118 specification of λδ version 1 is closed.<br>
 119           <span style="font-weight: bold;"></span></li>
 120       </ul>
 121       <ul>
 122         <li><span style="font-weight: bold;">March 2008.</span> The
 123 specification of λδ version 2 is started with Coq 7.3.1 (false start). </li>
 124       </ul>
 125 <!--          <ul>
 126             <li>native type assignment with new rules for application: <span
 127  style="font-style: italic;">nty</span> (it replaces <span
 128  style="font-style: italic;">ty3</span>);<br>
 129             </li>
 130             <li>parallel conversion on focalized terms: <span
 131  style="font-style: italic;">fpcs</span> (it replaces <span
 132  style="font-style: italic;"></span><span style="font-style: italic;">pc3</span>);
 133               <br>
 134             </li>
 135             <li>new weak parallel reduction on environments: <span
 136  style="font-style: italic;">wcpr</span> <span
 137  style="font-style: italic;"></span>(it is based on <span
 138  style="font-style: italic;">fpr</span> and replaces <span
 139  style="font-style: italic;">wcpr0</span>);&nbsp; <br>
 140             </li>
 141             <li>parallel reduction on focalized terms: <span
 142  style="font-style: italic;">fpr</span> and <span
 143  style="font-style: italic;">fprs</span> (they replace <span
 144  style="font-style: italic;"></span><span style="font-style: italic;"></span><span
 145  style="font-style: italic;">pr2</span>, <span
 146  style="font-style: italic;">pr3</span>); <br>
 147             </li>
 148           </ul>
 149           <ul>
 150             <li>new thinning relation: <span
 151  style="font-style: italic;">drop</span>
 152 (it replaces the old <span style="font-style: italic;">drop</span>, <span
 153  style="font-style: italic;">clear</span>, <span
 154  style="font-style: italic;">getl</span>, <span
 155  style="font-style: italic;">cimp</span>, <span
 156  style="font-style: italic;">drop1</span>);</li>
 157             <li>new shift function: <span style="font-style: italic;">shift</span>:
 158 (it
 159 replaces
 160
 161               <span style="font-style: italic;">app1</span>);</li>
 162             <li>new length function for environments: <span
 163  style="font-style: italic;">clen</span>;<br>
 164             </li>
 165             <li>new relocation function: <span
 166  style="font-style: italic;">lift</span> (it replaces old <span
 167  style="font-style: italic;">lift</span>, <span
 168  style="font-style: italic;">lift1</span>);<br>
 169             </li>
 170             <li>new term structure with polarity indicators and no
 171 distinction between binding and flat items;</li>
 172             <li>new general theory of relocation (comprises new
 173 relocation functions: <span style="font-style: italic;">s</span>, <span
 174  style="font-style: italic;">r</span>);</li>
 175             <li>we removed context-free reduction and conversion (<span
 176  style="font-style: italic;">pr0</span>, <span
 177  style="font-style: italic;">pr1</span>, <span
 178  style="font-style: italic;">pc1</span>);<br>
 179             </li>
 180             <li>we removed greedy substitution (<span
 181  style="font-style: italic;"></span><span style="font-style: italic;">csubst0</span>,
 182               <span style="font-style: italic;">csubst1</span>, <span
 183  style="font-style: italic;">fsubst0</span>, <span
 184  style="font-style: italic;">subst0</span>, <span
 185  style="font-style: italic;">subst1</span>);<br>
 186             </li>
 187             <li>we removed level indicators on environments (<span
 188  style="font-style: italic;">cbk</span>).</li>
 189           </ul>
 190 -->
 191       <ul>
 192         <li><span style="font-weight: bold;">September 2007.</span> The
 193           <a href="implementation.html#dynamic">specification of λδ
 194 version 1 for Matita 0.4</a> is online.</li>
 195       </ul>
 196       <ul>
 197         <li><span style="font-weight: bold;">November 2006.</span> <a href="documentation.html#ldp3">λδ version 1</a> is released.</li>
 198       </ul>
 199       <ul>
 200         <li><span style="font-weight: bold;">December 2005.</span> <a href="documentation.html#ldt1">First communication on λδ</a>.<br>
 201         </li>
 202       </ul>
 203       <ul>
 204         <li><span style="font-weight: bold;">May 2004.</span> The <a href="implementation.html#ldp1">specification of λδ version 1</a> is
 205 started with Coq 7.3.1.<br>
 206         </li>
 207       </ul>
 208       <h3 style="text-align: right;">Visibility <img style="width: 37px; height: 37px;" alt="[Butterfly]" title="Butterfly" src="images/b4.png"></h3>
 209       <ul>
 210         <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
 211 5 resources about λδ in the first 6 results.<br>
 212         </li>
 213       </ul>
 214       <ul>
 215         <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
 216 this site as the first result.</li>
 217       </ul>
 218       </td>
 219     </tr>
 220   </tbody>
 221 </table>
 222 <br>
 223 <a href="http://validator.w3.org/check?uri=referer"><img alt="[Valid HTML 4.01 Transitional]" title="Valid HTML 4.01
 224           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
 225           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>
 226 <br>
 227 Last update 2012-12-01 by <a href="http://www.cs.unibo.it/%7Efguidi/">Ferruccio
 228
 229 Guidi</a><br>
 230 </div>
 231
 232 </body></html>