helm/www/lambdadelta/news.html

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   6   <meta content="Ferruccio Guidi" name="author">
   7   <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]"
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  15 <h1>The Formal System λδ (\lambda\delta)<br>
  16 </h1>
  17 <h2>Towards the unification of terms, types, environments and contexts</h2>
  18 <img style="width: 95%; height: 4px;" alt="[Separator]"
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  26       <ul>
  27         <li><a href="index.html">Foreword</a></li>
  28       </ul>
  29       <ul>
  30         <li>News</li>
  31       </ul>
  32       <ul>
  33         <li><a href="documentation.html">Papers</a></li>
  34       </ul>
  35       <ul>
  36         <li><a href="implementation.html">Resources</a><br>
  37         </li>
  38       </ul>
  39       </td>
  40       <td style="vertical-align: top; text-align: left;">
  41       <h3 style="text-align: right;">News <img
  42  style="width: 37px; height: 37px;" alt="[Butterfly]" title="Butterfly"
  43  src="images/b5.png"></h3>
  44       <ul>
  45         <li><span style="font-weight: bold;">June 2014.</span> <a
  46  href="documentation.html#ldt8">First communication on λδ version 2.</a><br>
  47           <span style="font-weight: bold;"></span></li>
  48       </ul>
  49       <ul>
  50         <li><span style="font-weight: bold;">December 2012.</span> The
  51 character "_" is removed from the denomination "lambda_delta". </li>
  52       </ul>
  53       <ul>
  54         <ul>
  55           <li>The denomination "\lambda\delta" is used in λδ-related
  56 texts.</li>
  57           <li>The denomination "lambdadelta" is used in λδ-related
  58 identifiers.</li>
  59           <li>Permanent λδ URL acquired: <a
  60  href="http://lambdadelta.info/">http://lambdadelta.info/</a>
  61 (pointing at this site). </li>
  62         </ul>
  63       </ul>
  64       <ul>
  65         <li><span style="font-weight: bold;">September 2011.</span> The
  66 denomination "lambda-delta" changes to "lambda_delta".
  67           <ul>
  68             <li>The character "-" is reserved in λδ textual syntax
  69 (recognized by <span style="font-style: italic;">Helena 0.8.1</span>).
  70             </li>
  71             <li>Eventually, the occurrences of the character "-" will
  72 be replaced by "_" in all λδ-related identifiers.</li>
  73             <li>In particular, this refactoring involves file names and
  74 path names.</li>
  75           </ul>
  76         </li>
  77       </ul>
  78       <ul>
  79         <li><span style="font-weight: bold;">April 2011.</span> The
  80 specification of λδ version 2 and related topics is restarted in <a
  81  href="http://matita.cs.unibo.it/">Matita 0.5</a>.
  82           <ul>
  83             <li><a href="apps_2.html">Here</a> is a page about the
  84 topics related to the specification (Applications).</li>
  85             <li><a href="basic_2.html">Here</a> is a page about the
  86 specification (Core). </li>
  87             <li><a href="ground_2.html">Here</a> is a page about the
  88 background of the specification (Ground).</li>
  89           </ul>
  90         </li>
  91       </ul>
  92       <ul>
  93         <li><span style="font-weight: bold;">December 2010.</span>
  94 Transient λδ URL acquired: http://lambda-delta.info/
  95 (expires on December 2012). <br>
  96           <span style="font-weight: bold;"></span></li>
  97       </ul>
  98       <ul>
  99         <li><span style="font-weight: bold;">November 2010.</span> <span
 100  style="font-style: italic;">Helena 0.8.1</span> is released. <br>
 101         </li>
 102       </ul>
 103       <ul>
 104         <li><span style="font-weight: bold;">September 2009.</span> <span
 105  style="font-style: italic;">Helena 0.8.0</span> is released and the <a
 106  href="implementation.html#lddl">λδ Digital Library</a> is started.<br>
 107           <span style="font-weight: bold;"></span></li>
 108       </ul>
 109       <ul>
 110         <li><span style="font-weight: bold;">June 2009.</span> <span
 111  style="font-style: italic;">Helena</span>, a <a
 112  href="implementation.html#helena">validator for λδ version 2</a>, is
 113 available as a part of the <a href="http://helm.cs.unibo.it/">HELM</a>
 114 software. <br>
 115         </li>
 116       </ul>
 117       <span style="font-weight: bold;"></span>
 118       <ul>
 119         <li><span style="font-weight: bold;">September 2008.</span>
 120 This site is online.<br>
 121         </li>
 122       </ul>
 123       <span style="font-weight: bold;"></span>
 124       <ul>
 125         <li><span style="font-weight: bold;">July 2008.</span> <a
 126  href="documentation.html#ldp5">First journal paper on λδ</a> accepted
 127 for publication.</li>
 128       </ul>
 129       <ul>
 130         <li><span style="font-weight: bold;">July 2008.</span> First <a
 131  href="http://helm.cs.unibo.it/procedural/">procedural reconstruction</a>
 132 for <a href="http://matita.cs.unibo.it/">Matita 0.5</a> of the <a
 133  href="implementation.html#ldp1">λδ proof scripts for Coq 7.3.1</a>.<br>
 134         </li>
 135       </ul>
 136       <ul>
 137         <li><span style="font-weight: bold;">June 2008.</span> The <a
 138  href="implementation.html#static">HTML pages of the specification of
 139 λδ version 1 for Matita 0.5</a> are online.<br>
 140           <span style="font-weight: bold;"></span></li>
 141       </ul>
 142       <ul>
 143         <li><span style="font-weight: bold;">May 2008.</span> The
 144 specification of λδ version 1 is dismissed.<br>
 145           <span style="font-weight: bold;"></span></li>
 146       </ul>
 147       <ul>
 148         <li><span style="font-weight: bold;">March 2008.</span> The
 149 specification of λδ version 2 is started with Coq 7.3.1 (false start). </li>
 150       </ul>
 151 <!--          <ul>
 152             <li>native type assignment with new rules for application: <span
 153  style="font-style: italic;">nty</span> (it replaces <span
 154  style="font-style: italic;">ty3</span>);<br>
 155             </li>
 156             <li>parallel conversion on focalized terms: <span
 157  style="font-style: italic;">fpcs</span> (it replaces <span
 158  style="font-style: italic;"></span><span style="font-style: italic;">pc3</span>);
 159               <br>
 160             </li>
 161             <li>new weak parallel reduction on environments: <span
 162  style="font-style: italic;">wcpr</span> <span
 163  style="font-style: italic;"></span>(it is based on <span
 164  style="font-style: italic;">fpr</span> and replaces <span
 165  style="font-style: italic;">wcpr0</span>);&nbsp; <br>
 166             </li>
 167             <li>parallel reduction on focalized terms: <span
 168  style="font-style: italic;">fpr</span> and <span
 169  style="font-style: italic;">fprs</span> (they replace <span
 170  style="font-style: italic;"></span><span style="font-style: italic;"></span><span
 171  style="font-style: italic;">pr2</span>, <span
 172  style="font-style: italic;">pr3</span>); <br>
 173             </li>
 174           </ul>
 175           <ul>
 176             <li>new thinning relation: <span
 177  style="font-style: italic;">drop</span>
 178 (it replaces the old <span style="font-style: italic;">drop</span>, <span
 179  style="font-style: italic;">clear</span>, <span
 180  style="font-style: italic;">getl</span>, <span
 181  style="font-style: italic;">cimp</span>, <span
 182  style="font-style: italic;">drop1</span>);</li>
 183             <li>new shift function: <span style="font-style: italic;">shift</span>:
 184 (it
 185 replaces
 186
 187               <span style="font-style: italic;">app1</span>);</li>
 188             <li>new length function for environments: <span
 189  style="font-style: italic;">clen</span>;<br>
 190             </li>
 191             <li>new relocation function: <span
 192  style="font-style: italic;">lift</span> (it replaces old <span
 193  style="font-style: italic;">lift</span>, <span
 194  style="font-style: italic;">lift1</span>);<br>
 195             </li>
 196             <li>new term structure with polarity indicators and no
 197 distinction between binding and flat items;</li>
 198             <li>new general theory of relocation (comprises new
 199 relocation functions: <span style="font-style: italic;">s</span>, <span
 200  style="font-style: italic;">r</span>);</li>
 201             <li>we removed context-free reduction and conversion (<span
 202  style="font-style: italic;">pr0</span>, <span
 203  style="font-style: italic;">pr1</span>, <span
 204  style="font-style: italic;">pc1</span>);<br>
 205             </li>
 206             <li>we removed greedy substitution (<span
 207  style="font-style: italic;"></span><span style="font-style: italic;">csubst0</span>,
 208               <span style="font-style: italic;">csubst1</span>, <span
 209  style="font-style: italic;">fsubst0</span>, <span
 210  style="font-style: italic;">subst0</span>, <span
 211  style="font-style: italic;">subst1</span>);<br>
 212             </li>
 213             <li>we removed level indicators on environments (<span
 214  style="font-style: italic;">cbk</span>).</li>
 215           </ul>
 216 -->
 217       <ul>
 218         <li><span style="font-weight: bold;">September 2007.</span> The
 219           <a href="implementation.html#dynamic">specification of λδ
 220 version 1 for Matita 0.4</a> is online.</li>
 221       </ul>
 222       <ul>
 223         <li><span style="font-weight: bold;">November 2006.</span> <a
 224  href="documentation.html#ldp3">λδ version 1</a> is released.</li>
 225       </ul>
 226       <ul>
 227         <li><span style="font-weight: bold;">December 2005.</span> <a
 228  href="documentation.html#ldt1">First communication on λδ</a>.<br>
 229         </li>
 230       </ul>
 231       <ul>
 232         <li><span style="font-weight: bold;">May 2004.</span> The <a
 233  href="implementation.html#ldp1">specification of λδ version 1</a> is
 234 started with Coq 7.3.1.<br>
 235         </li>
 236       </ul>
 237       <h3 style="text-align: right;">Visibility <img
 238  style="width: 37px; height: 37px;" alt="[Butterfly]" title="Butterfly"
 239  src="images/b4.png"></h3>
 240       <ul>
 241         <li><span style="font-weight: bold;">June 2014.</span> The <a
 242  href="http://www.google.com/">Google</a> search for <span
 243  style="color: rgb(255, 0, 0);">formal system lambda delta</span> gives
 244 5 resources about λδ in the first 6 results.<br>
 245         </li>
 246       </ul>
 247       <ul>
 248         <li><span style="font-weight: bold;">June 2014.</span> The <a
 249  href="http://www.yahoo.com/">Yahoo</a> search <span
 250  style="color: rgb(255, 0, 0);">formal system lambda delta</span> gives
 251 4 resources about λδ in the first 5 results.</li>
 252       </ul>
 253       </td>
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 272 Last update 2014-06-19 by <a href="http://www.cs.unibo.it/%7Efguidi/">Ferruccio
 273 Guidi</a><br>
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