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           </ul>
  75         </li>
  76       </ul>
  77       <ul>
  78         <li><span style="font-weight: bold;">December 2010.</span> Transient λδ URL acquired: http://lambda-delta.info/
  79 (expires on December 2012). <br>
  80           <span style="font-weight: bold;"></span></li>
  81       </ul>
  82       <ul>
  83         <li><span style="font-weight: bold;">November 2010.</span> <span style="font-style: italic;">Helena 0.8.1</span> is released. <br>
  84         </li>
  85       </ul>
  86       <ul>
  87         <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>
  88           <span style="font-weight: bold;"></span></li>
  89       </ul>
  90       <ul>
  91         <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
  92 available as a part of the <a href="http://helm.cs.unibo.it/">HELM</a>
  93 software. <br>
  94         </li>
  95       </ul>
  96       <span style="font-weight: bold;"></span>
  97       <ul>
  98         <li><span style="font-weight: bold;">September 2008.</span>
  99 This site is online.<br>
 100         </li>
 101       </ul>
 102       <span style="font-weight: bold;"></span>
 103       <ul>
 104         <li><span style="font-weight: bold;">July 2008.</span> <a href="documentation.html#ldp5">First journal paper on λδ</a> accepted
 105 for publication.</li>
 106       </ul>
 107       <ul>
 108         <li><span style="font-weight: bold;">July 2008.</span> First <a href="http://helm.cs.unibo.it/procedural/">procedural reconstruction</a>
 109 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>
 110         </li>
 111       </ul>
 112       <ul>
 113         <li><span style="font-weight: bold;">June 2008.</span> The <a href="implementation.html#static">HTML pages of the specification of
 114 λδ version 1 for Matita 0.5</a> are online.<br>
 115           <span style="font-weight: bold;"></span></li>
 116       </ul>
 117       <ul>
 118         <li><span style="font-weight: bold;">May 2008.</span> The
 119 specification of λδ version 1 is dismissed.<br>
 120           <span style="font-weight: bold;"></span></li>
 121       </ul>
 122       <ul>
 123         <li><span style="font-weight: bold;">March 2008.</span> The
 124 specification of λδ version 2 is started with Coq 7.3.1 (false start). </li>
 125       </ul>
 126 <!--          <ul>
 127             <li>native type assignment with new rules for application: <span
 128  style="font-style: italic;">nty</span> (it replaces <span
 129  style="font-style: italic;">ty3</span>);<br>
 130             </li>
 131             <li>parallel conversion on focalized terms: <span
 132  style="font-style: italic;">fpcs</span> (it replaces <span
 133  style="font-style: italic;"></span><span style="font-style: italic;">pc3</span>);
 134               <br>
 135             </li>
 136             <li>new weak parallel reduction on environments: <span
 137  style="font-style: italic;">wcpr</span> <span
 138  style="font-style: italic;"></span>(it is based on <span
 139  style="font-style: italic;">fpr</span> and replaces <span
 140  style="font-style: italic;">wcpr0</span>);&nbsp; <br>
 141             </li>
 142             <li>parallel reduction on focalized terms: <span
 143  style="font-style: italic;">fpr</span> and <span
 144  style="font-style: italic;">fprs</span> (they replace <span
 145  style="font-style: italic;"></span><span style="font-style: italic;"></span><span
 146  style="font-style: italic;">pr2</span>, <span
 147  style="font-style: italic;">pr3</span>); <br>
 148             </li>
 149           </ul>
 150           <ul>
 151             <li>new thinning relation: <span
 152  style="font-style: italic;">drop</span>
 153 (it replaces the old <span style="font-style: italic;">drop</span>, <span
 154  style="font-style: italic;">clear</span>, <span
 155  style="font-style: italic;">getl</span>, <span
 156  style="font-style: italic;">cimp</span>, <span
 157  style="font-style: italic;">drop1</span>);</li>
 158             <li>new shift function: <span style="font-style: italic;">shift</span>:
 159 (it
 160 replaces
 161
 162               <span style="font-style: italic;">app1</span>);</li>
 163             <li>new length function for environments: <span
 164  style="font-style: italic;">clen</span>;<br>
 165             </li>
 166             <li>new relocation function: <span
 167  style="font-style: italic;">lift</span> (it replaces old <span
 168  style="font-style: italic;">lift</span>, <span
 169  style="font-style: italic;">lift1</span>);<br>
 170             </li>
 171             <li>new term structure with polarity indicators and no
 172 distinction between binding and flat items;</li>
 173             <li>new general theory of relocation (comprises new
 174 relocation functions: <span style="font-style: italic;">s</span>, <span
 175  style="font-style: italic;">r</span>);</li>
 176             <li>we removed context-free reduction and conversion (<span
 177  style="font-style: italic;">pr0</span>, <span
 178  style="font-style: italic;">pr1</span>, <span
 179  style="font-style: italic;">pc1</span>);<br>
 180             </li>
 181             <li>we removed greedy substitution (<span
 182  style="font-style: italic;"></span><span style="font-style: italic;">csubst0</span>,
 183               <span style="font-style: italic;">csubst1</span>, <span
 184  style="font-style: italic;">fsubst0</span>, <span
 185  style="font-style: italic;">subst0</span>, <span
 186  style="font-style: italic;">subst1</span>);<br>
 187             </li>
 188             <li>we removed level indicators on environments (<span
 189  style="font-style: italic;">cbk</span>).</li>
 190           </ul>
 191 -->
 192       <ul>
 193         <li><span style="font-weight: bold;">September 2007.</span> The
 194           <a href="implementation.html#dynamic">specification of λδ
 195 version 1 for Matita 0.4</a> is online.</li>
 196       </ul>
 197       <ul>
 198         <li><span style="font-weight: bold;">November 2006.</span> <a href="documentation.html#ldp3">λδ version 1</a> is released.</li>
 199       </ul>
 200       <ul>
 201         <li><span style="font-weight: bold;">December 2005.</span> <a href="documentation.html#ldt1">First communication on λδ</a>.<br>
 202         </li>
 203       </ul>
 204       <ul>
 205         <li><span style="font-weight: bold;">May 2004.</span> The <a href="implementation.html#ldp1">specification of λδ version 1</a> is
 206 started with Coq 7.3.1.<br>
 207         </li>
 208       </ul>
 209       <h3 style="text-align: right;">Visibility <img style="width: 37px; height: 37px;" alt="[Butterfly]" title="Butterfly" src="images/b4.png"></h3>
 210       <ul>
 211         <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
 212 5 resources about λδ in the first 6 results.<br>
 213         </li>
 214       </ul>
 215       <ul>
 216         <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
 217 this site as the first result.</li>
 218       </ul>
 219       </td>
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 228 Last update 2012-12-02 by <a href="http://www.cs.unibo.it/%7Efguidi/">Ferruccio
 229
 230 Guidi</a><br>
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