helm/www/lambda_delta/news.html

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   6   <meta content="Ferruccio Guidi" name="author">
   7   <meta content="The formal system lambda_delta" name="description">
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  13 <a href="http://lambda-delta.info"><img alt="[Crux Logo]"
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  16 <h1>The Formal System λδ (lambda_delta)<br>
  17 </h1>
  18 <h2>Towards the unification of terms, types, environments and contexts</h2>
  19 <img style="width: 95%; height: 4px;" alt="[Separator]"
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  27       <ul>
  28         <li><a href="index.html">Foreword</a></li>
  29       </ul>
  30       <ul>
  31         <li>News</li>
  32       </ul>
  33       <ul>
  34         <li><a href="documentation.html">Papers</a></li>
  35       </ul>
  36       <ul>
  37         <li><a href="implementation.html">Resources</a><br>
  38         </li>
  39       </ul>
  40       </td>
  41       <td style="vertical-align: top; text-align: left;">
  42       <h3 style="text-align: right;">News <img
  43  style="width: 37px; height: 37px;" alt="[Butterfly]" title="Butterfly"
  44  src="download/b5.png"></h3>
  45       <ul>
  46         <li><span style="font-weight: bold;">September 2011.</span> The
  47 denomination "lambda-delta" changes to "lambda_delta".</li>
  48         <ul>
  49           <li>The character "-" is reserved in λδ textual syntax
  50 (recognized by <span style="font-style: italic;">Helena 0.8.1</span>).<br>
  51           </li>
  52           <li>Eventually, the occurrences of the character "-" will be
  53 replaced by "_" in all λδ-related identifiers.</li>
  54           <li>In particular, this refactoring involves file names and
  55 path names.</li>
  56           <li>The permanent λδ URL is sheduled to become <span
  57  style="font-style: italic;">http://lambda_delta.info</span> on December 2012.<br>
  58           </li>
  59         </ul>
  60       </ul>
  61       <ul>
  62         <li><span style="font-weight: bold;">April 2011.</span> The
  63 specification of λδ version 2 is restarted in <a
  64  href="http://matita.cs.unibo.it/">Matita 0.5</a>.</li>
  65         <ul>
  66           <li><a href="ld_basic_2.html">Here</a> is a page about the
  67 specification.<br>
  68           </li>
  69         </ul>
  70       </ul>
  71       <ul>
  72         <li><span style="font-weight: bold;">December 2010.</span>
  73 Permanent λδ URL acquired: <a href="http://lambda-delta.info">http://lambda-delta.info</a>
  74 (pointing at this site). <br>
  75           <span style="font-weight: bold;"></span></li>
  76       </ul>
  77       <ul>
  78         <li><span style="font-weight: bold;">November 2010.</span> <span
  79  style="font-style: italic;">Helena 0.8.1</span> is released. <br>
  80         </li>
  81       </ul>
  82       <ul>
  83         <li><span style="font-weight: bold;">September 2009.</span> <span
  84  style="font-style: italic;">Helena 0.8.0</span> is released and the <a
  85  href="implementation.html#lddl">λδ Digital Library</a> is
  86 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
  91  style="font-style: italic;">Helena</span>, A <a
  92  href="implementation.html#helena">validator for </a><a
  93  href="implementation.html#helena">λδ</a><span
  94  style="font-style: italic;"></span>, <span style="font-style: italic;"></span>is
  95 available
  96 as
  97 a
  98 part
  99 of
 100 the
 101           <a href="http://helm.cs.unibo.it/">HELM</a> software. <br>
 102         </li>
 103       </ul>
 104       <span style="font-weight: bold;"></span>
 105       <ul>
 106         <li><span style="font-weight: bold;">September 2008.</span>
 107 This site is online.<br>
 108         </li>
 109       </ul>
 110       <span style="font-weight: bold;"></span>
 111       <ul>
 112         <li><span style="font-weight: bold;">July 2008.</span> <a
 113  href="documentation.html#tocl1">First journal paper on λδ</a> accepted
 114 for publication.</li>
 115       </ul>
 116       <ul>
 117         <li><span style="font-weight: bold;">July 2008.</span> First <a
 118  href="http://helm.cs.unibo.it/procedural/">procedural
 119 reconstruction</a> in <a href="http://matita.cs.unibo.it/">Matita 0.5</a>
 120 of the <a href="implementation.html#source">λδ proof scripts in
 121 Coq 7.3.1</a>.<br>
 122         </li>
 123       </ul>
 124       <ul>
 125         <li><span style="font-weight: bold;">June 2008.</span> The <a
 126  href="implementation.html#static">HTML
 127 pages of the specification of λδ in Matita 0.5</a> are online.<br>
 128           <span style="font-weight: bold;"></span></li>
 129       </ul>
 130       <ul>
 131         <li><span style="font-weight: bold;">March 2008.</span> The
 132 specification of λδ version 2 begins in Coq 7.3.1 (false start).
 133 <!--          <ul>
 134             <li>native type assignment with new rules for application: <span
 135  style="font-style: italic;">nty</span> (it replaces <span
 136  style="font-style: italic;">ty3</span>);<br>
 137             </li>
 138             <li>parallel conversion on focalized terms: <span
 139  style="font-style: italic;">fpcs</span> (it replaces <span
 140  style="font-style: italic;"></span><span style="font-style: italic;">pc3</span>);
 141               <br>
 142             </li>
 143             <li>new weak parallel reduction on environments: <span
 144  style="font-style: italic;">wcpr</span> <span
 145  style="font-style: italic;"></span>(it is based on <span
 146  style="font-style: italic;">fpr</span> and replaces <span
 147  style="font-style: italic;">wcpr0</span>);&nbsp; <br>
 148             </li>
 149             <li>parallel reduction on focalized terms: <span
 150  style="font-style: italic;">fpr</span> and <span
 151  style="font-style: italic;">fprs</span> (they replace <span
 152  style="font-style: italic;"></span><span style="font-style: italic;"></span><span
 153  style="font-style: italic;">pr2</span>, <span
 154  style="font-style: italic;">pr3</span>); <br>
 155             </li>
 156           </ul>
 157           <ul>
 158             <li>new thinning relation: <span
 159  style="font-style: italic;">drop</span>
 160 (it replaces the old <span style="font-style: italic;">drop</span>, <span
 161  style="font-style: italic;">clear</span>, <span
 162  style="font-style: italic;">getl</span>, <span
 163  style="font-style: italic;">cimp</span>, <span
 164  style="font-style: italic;">drop1</span>);</li>
 165             <li>new shift function: <span style="font-style: italic;">shift</span>:
 166 (it
 167 replaces
 168
 169               <span style="font-style: italic;">app1</span>);</li>
 170             <li>new length function for environments: <span
 171  style="font-style: italic;">clen</span>;<br>
 172             </li>
 173             <li>new relocation function: <span
 174  style="font-style: italic;">lift</span> (it replaces old <span
 175  style="font-style: italic;">lift</span>, <span
 176  style="font-style: italic;">lift1</span>);<br>
 177             </li>
 178             <li>new term structure with polarity indicators and no
 179 distinction between binding and flat items;</li>
 180             <li>new general theory of relocation (comprises new
 181 relocation functions: <span style="font-style: italic;">s</span>, <span
 182  style="font-style: italic;">r</span>);</li>
 183             <li>we removed context-free reduction and conversion (<span
 184  style="font-style: italic;">pr0</span>, <span
 185  style="font-style: italic;">pr1</span>, <span
 186  style="font-style: italic;">pc1</span>);<br>
 187             </li>
 188             <li>we removed greedy substitution (<span
 189  style="font-style: italic;"></span><span style="font-style: italic;">csubst0</span>,
 190               <span style="font-style: italic;">csubst1</span>, <span
 191  style="font-style: italic;">fsubst0</span>, <span
 192  style="font-style: italic;">subst0</span>, <span
 193  style="font-style: italic;">subst1</span>);<br>
 194             </li>
 195             <li>we removed level indicators on environments (<span
 196  style="font-style: italic;">cbk</span>).</li>
 197           </ul>
 198 --> </li>
 199       </ul>
 200       <ul>
 201         <li><span style="font-weight: bold;">September 2007.</span>
 202 The <a href="implementation.html#dynamic">specification of λδ in
 203 Matita 0.4</a> is online.<br>
 204         </li>
 205       </ul>
 206       <ul>
 207         <li><span style="font-weight: bold;">December 2005.</span> <a
 208  href="documentation.html#bologna1">First communication on λδ</a>.<br>
 209         </li>
 210       </ul>
 211       <ul>
 212         <li><span style="font-weight: bold;">May 2004.</span> The <a
 213  href="implementation.html#source">specification of λδ in
 214 Coq 7.3.1</a> begins.<br>
 215         </li>
 216       </ul>
 217       <h3 style="text-align: right;">Visibility <img
 218  style="width: 37px; height: 37px;" alt="[Butterfly]" title="Butterfly"
 219  src="download/b4.png"></h3>
 220       <ul>
 221         <li><span style="font-weight: bold;">November 2010.</span>
 222 The <a href="http://www.google.com/">Google</a>
 223 search <span style="color: rgb(255, 0, 0);">formal system lambda delta</span>
 224 gives 8 resources about λδ as the first results.<br>
 225         </li>
 226       </ul>
 227       <ul>
 228         <li><span style="font-weight: bold;">November 2010.</span>
 229 The <a href="http://www.yahoo.com/">Yahoo</a>
 230 search <span style="color: rgb(255, 0, 0);">formal system lambda delta</span>
 231 gives 4 resources and 2 sub-resources about λδ as the first results.</li>
 232       </ul>
 233       </td>
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 251 Guidi</a><br>
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