helm/www/lambdadelta/news.html

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   7
   8   <meta content="Ferruccio Guidi" name="author">
   9   <meta content="The formal system λδ" name="description">
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  11 <div style="text-align: center;"> <br>
  12 <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>
  13 <h1>The Formal System λδ (\lambda\delta)<br>
  14 </h1>
  15 <h2>Towards the unification of terms, types, environments and contexts</h2>
  16 <img style="width: 95%; height: 4px;" alt="[Separator]" title="Separator" src="images/rainbow.png"><br>
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  21       <ul>
  22         <li><a href="index.html">Foreword</a></li>
  23       </ul>
  24       <ul>
  25         <li>News</li>
  26       </ul>
  27       <ul>
  28         <li><a href="documentation.html">Papers</a></li>
  29       </ul>
  30       <ul>
  31         <li><a href="implementation.html">Resources</a><br>
  32         </li>
  33       </ul>
  34       </td>
  35       <td style="vertical-align: top; text-align: left;">
  36       <h3 style="text-align: right;">News <img style="width: 37px; height: 37px;" alt="[Butterfly]" title="Butterfly" src="images/b5.png"></h3>
  37       <ul>
  38
  39         <li><span style="font-weight: bold;">December 2012.</span> The character "_" is removed from the denomination "lambda_delta". <br>
  40         </li>
  41         <ul>
  42           <li>The denomination "\lambda\delta" is used in λδ-related texts.</li>
  43           <li>The denomination "lambdadelta" is used in λδ-related identifiers.</li>
  44           <li>Permanent λδ URL acquired: <a href="http://lambdadelta.info/">http://lambdadelta.info/</a>
  45 (pointing at this site). </li>
  46         </ul>
  47 </ul>
  48       <ul>
  49         <li><span style="font-weight: bold;">September 2011.</span> The
  50 denomination "lambda-delta" changes to "lambda_delta".
  51           <ul>
  52             <li>The character "-" is reserved in λδ textual syntax
  53 (recognized by <span style="font-style: italic;">Helena 0.8.1</span>).
  54             </li>
  55             <li>Eventually, the occurrences of the character "-" will
  56 be replaced by "_" in all λδ-related identifiers.</li>
  57             <li>In particular, this refactoring involves file names and
  58 path names.</li>
  59
  60           </ul>
  61         </li>
  62
  63
  64       </ul>
  65
  66       <ul>
  67         <li><span style="font-weight: bold;">April 2011.</span> The
  68 specification of λδ version 2 and related topics is restarted in <a href="http://matita.cs.unibo.it/">Matita 0.5</a>.
  69           <ul>
  70             <li><a href="apps_2.html">Here</a> is a page about the
  71 topics related to the specification (Applications).</li>
  72             <li><a href="basic_2.html">Here</a> is a page about the
  73 specification (Core). </li>
  74             <li><a href="ground_2.html">Here</a> is a page about the
  75 background of the specification (Ground).</li>
  76           </ul>
  77         </li>
  78       </ul>
  79       <ul>
  80         <li><span style="font-weight: bold;">December 2010.</span> Transient λδ URL acquired: http://lambda-delta.info/
  81 (expires on December 2012). <br>
  82           <span style="font-weight: bold;"></span></li>
  83       </ul>
  84       <ul>
  85         <li><span style="font-weight: bold;">November 2010.</span> <span style="font-style: italic;">Helena 0.8.1</span> is released. <br>
  86         </li>
  87       </ul>
  88       <ul>
  89         <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>
  90           <span style="font-weight: bold;"></span></li>
  91       </ul>
  92       <ul>
  93         <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
  94 available as a part of the <a href="http://helm.cs.unibo.it/">HELM</a>
  95 software. <br>
  96         </li>
  97       </ul>
  98       <span style="font-weight: bold;"></span>
  99       <ul>
 100         <li><span style="font-weight: bold;">September 2008.</span>
 101 This site is online.<br>
 102         </li>
 103       </ul>
 104       <span style="font-weight: bold;"></span>
 105       <ul>
 106         <li><span style="font-weight: bold;">July 2008.</span> <a href="documentation.html#ldp5">First journal paper on λδ</a> accepted
 107 for publication.</li>
 108       </ul>
 109       <ul>
 110         <li><span style="font-weight: bold;">July 2008.</span> First <a href="http://helm.cs.unibo.it/procedural/">procedural reconstruction</a>
 111 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>
 112         </li>
 113       </ul>
 114       <ul>
 115         <li><span style="font-weight: bold;">June 2008.</span> The <a href="implementation.html#static">HTML pages of the specification of
 116 λδ version 1 for Matita 0.5</a> are online.<br>
 117           <span style="font-weight: bold;"></span></li>
 118       </ul>
 119       <ul>
 120         <li><span style="font-weight: bold;">May 2008.</span> The
 121 specification of λδ version 1 is dismissed.<br>
 122           <span style="font-weight: bold;"></span></li>
 123       </ul>
 124       <ul>
 125         <li><span style="font-weight: bold;">March 2008.</span> The
 126 specification of λδ version 2 is started with Coq 7.3.1 (false start). </li>
 127       </ul>
 128 <!--          <ul>
 129             <li>native type assignment with new rules for application: <span
 130  style="font-style: italic;">nty</span> (it replaces <span
 131  style="font-style: italic;">ty3</span>);<br>
 132             </li>
 133             <li>parallel conversion on focalized terms: <span
 134  style="font-style: italic;">fpcs</span> (it replaces <span
 135  style="font-style: italic;"></span><span style="font-style: italic;">pc3</span>);
 136               <br>
 137             </li>
 138             <li>new weak parallel reduction on environments: <span
 139  style="font-style: italic;">wcpr</span> <span
 140  style="font-style: italic;"></span>(it is based on <span
 141  style="font-style: italic;">fpr</span> and replaces <span
 142  style="font-style: italic;">wcpr0</span>);&nbsp; <br>
 143             </li>
 144             <li>parallel reduction on focalized terms: <span
 145  style="font-style: italic;">fpr</span> and <span
 146  style="font-style: italic;">fprs</span> (they replace <span
 147  style="font-style: italic;"></span><span style="font-style: italic;"></span><span
 148  style="font-style: italic;">pr2</span>, <span
 149  style="font-style: italic;">pr3</span>); <br>
 150             </li>
 151           </ul>
 152           <ul>
 153             <li>new thinning relation: <span
 154  style="font-style: italic;">drop</span>
 155 (it replaces the old <span style="font-style: italic;">drop</span>, <span
 156  style="font-style: italic;">clear</span>, <span
 157  style="font-style: italic;">getl</span>, <span
 158  style="font-style: italic;">cimp</span>, <span
 159  style="font-style: italic;">drop1</span>);</li>
 160             <li>new shift function: <span style="font-style: italic;">shift</span>:
 161 (it
 162 replaces
 163
 164               <span style="font-style: italic;">app1</span>);</li>
 165             <li>new length function for environments: <span
 166  style="font-style: italic;">clen</span>;<br>
 167             </li>
 168             <li>new relocation function: <span
 169  style="font-style: italic;">lift</span> (it replaces old <span
 170  style="font-style: italic;">lift</span>, <span
 171  style="font-style: italic;">lift1</span>);<br>
 172             </li>
 173             <li>new term structure with polarity indicators and no
 174 distinction between binding and flat items;</li>
 175             <li>new general theory of relocation (comprises new
 176 relocation functions: <span style="font-style: italic;">s</span>, <span
 177  style="font-style: italic;">r</span>);</li>
 178             <li>we removed context-free reduction and conversion (<span
 179  style="font-style: italic;">pr0</span>, <span
 180  style="font-style: italic;">pr1</span>, <span
 181  style="font-style: italic;">pc1</span>);<br>
 182             </li>
 183             <li>we removed greedy substitution (<span
 184  style="font-style: italic;"></span><span style="font-style: italic;">csubst0</span>,
 185               <span style="font-style: italic;">csubst1</span>, <span
 186  style="font-style: italic;">fsubst0</span>, <span
 187  style="font-style: italic;">subst0</span>, <span
 188  style="font-style: italic;">subst1</span>);<br>
 189             </li>
 190             <li>we removed level indicators on environments (<span
 191  style="font-style: italic;">cbk</span>).</li>
 192           </ul>
 193 -->
 194       <ul>
 195         <li><span style="font-weight: bold;">September 2007.</span> The
 196           <a href="implementation.html#dynamic">specification of λδ
 197 version 1 for Matita 0.4</a> is online.</li>
 198       </ul>
 199       <ul>
 200         <li><span style="font-weight: bold;">November 2006.</span> <a href="documentation.html#ldp3">λδ version 1</a> is released.</li>
 201       </ul>
 202       <ul>
 203         <li><span style="font-weight: bold;">December 2005.</span> <a href="documentation.html#ldt1">First communication on λδ</a>.<br>
 204         </li>
 205       </ul>
 206       <ul>
 207         <li><span style="font-weight: bold;">May 2004.</span> The <a href="implementation.html#ldp1">specification of λδ version 1</a> is
 208 started with Coq 7.3.1.<br>
 209         </li>
 210       </ul>
 211       <h3 style="text-align: right;">Visibility <img style="width: 37px; height: 37px;" alt="[Butterfly]" title="Butterfly" src="images/b4.png"></h3>
 212       <ul>
 213         <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
 214 5 resources about λδ in the first 6 results.<br>
 215         </li>
 216       </ul>
 217       <ul>
 218         <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
 219 this site as the first result.</li>
 220       </ul>
 221       </td>
 222     </tr>
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 230 Last update 2013-10-27 by <a href="http://www.cs.unibo.it/%7Efguidi/">Ferruccio
 231
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