1 <?xml version="1.0" encoding="UTF-8"?>
2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
3 <html xmlns="http://www.w3.org/1999/xhtml" dir="ltr" lang="en-us">
5 <meta http-equiv="Content-Language" content="en-us" />
6 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
7 <meta http-equiv="Content-Style-Type" content="text/css" />
8 <meta name="author" content="Ferruccio Guidi" />
9 <meta name="description" content="\lambda\delta home page" />
10 <title>\lambda\delta home page</title>
11 <link rel="stylesheet" type="text/css" href="http://lambdadelta.info/css/ld_web.css" />
12 <link rel="stylesheet" type="text/css" href="http://lambdadelta.info/css/lddl.css" />
13 <link rel="stylesheet" type="text/css" href="http://lambdadelta.info/css/xhtbl.css" />
14 <link rel="shortcut icon" href="http://lambdadelta.info/images/crux_16.ico" />
18 <a href="http://lambdadelta.info/">
19 <img class="icon32" alt="[lambdadelta home]" title="lambdadelta home" src="http://lambdadelta.info/images/crux_32.png" />
22 <div class="head1">The Formal System λδ (\lambda\delta)</div>
24 <img class="rule" alt="[Spacer]" title="lambdadelta rainbow rule" src="http://lambdadelta.info/images/rainbow.png" />
26 <div xmlns:ld="http://lambdadelta.info/" class="spacer">
29 <div xmlns:ld="http://lambdadelta.info/" class="text">
30 <table cellpadding="4" cellspacing="0">
33 <td class="snns component sky">
34 <a href="http://lambdadelta.info/index.html">home</a>
36 <td class="snns component magenta">
37 <a href="http://lambdadelta.info/news.html">news</a>
39 <td class="snns component orange">
40 <a href="http://lambdadelta.info/documentation.html">documentation</a>
42 <td class="snns component green">
43 <a href="http://lambdadelta.info/implementation.html">implementation</a>
45 <td class="ssnn component green">
51 <a href="http://lambdadelta.info/index.html#foreword">Foreword</a>
53 <td class="snns magenta">
54 <a href="http://lambdadelta.info/news.html#milestones">Milestones</a>
56 <td class="snns orange">
57 <a href="http://lambdadelta.info/documentation.html#v2">Version 2</a>
59 <td class="snns green">
60 <a href="http://lambdadelta.info/version_2.html">Version 2</a>
62 <td class="ssnn green">
63 <a href="http://lambdadelta.info/ground_2.html">Background</a>
64 <a href="http://lambdadelta.info/basic_2.html">Core</a>
65 <a href="http://lambdadelta.info/apps_2.html">Applications</a>
70 <a href="http://lambdadelta.info/index.html#notice">Notice</a>
72 <td class="snss magenta">
73 <a href="http://lambdadelta.info/news.html#visibility">Visibility</a>
75 <td class="snss orange">
76 <a href="http://lambdadelta.info/documentation.html#v1">Version 1</a>
78 <td class="snss green">
79 <a href="http://lambdadelta.info/version_1.html">Version 1</a>
81 <td class="sssn green">
89 <div xmlns:ld="http://lambdadelta.info/" class="head2dx" id="milestones">Milestones <img class="icon37" alt="[spacer]" title="lambdadelta butterfly" src="http://lambdadelta.info/images/b5.png" />
91 <div xmlns:ld="http://lambdadelta.info/" class="text">
94 <span class="date">June 2014.</span>
95 <a href="http://lambdadelta.info/documentation.html#ldt8">First communication on λδ version 2.</a>
100 <span class="date">December 2012.</span>
101 The character "_" is removed from the denomination "lambda_delta":
104 The denomination "\lambda\delta" is used in λδ-related texts.
107 The denomination "lambdadelta" is used in λδ-related identifiers.
110 Permanent λδ URL acquired:
111 <a href="http://lambdadelta.info/">http://lambdadelta.info/</a>
112 (pointing at this site).
119 <span class="date">September 2011.</span>
120 The denomination "lambda-delta" changes to "lambda_delta":
123 The character "-" is reserved in λδ textual syntax
124 (recognized by "Helena 0.8.1").
127 Eventually, the occurrences of the character "-"
128 will be replaced by "_" in all λδ-related identifiers.
131 In particular, this refactoring involves file names and path names.
138 <span class="date">April 2011.</span>
139 The specification of <a href="http://lambdadelta.info/version_2.html">λδ version 2</a>
140 and related topics is restarted in
141 <a href="http://matita.cs.unibo.it/">Matita 0.5</a>.
146 <span class="date">December 2010.</span>
147 Transient λδ URL acquired: http://lambda-delta.info/ (expires on December 2012).
152 <span class="date">November 2010.</span>
153 "Helena 0.8.1" is released.
158 <span class="date">September 2009.</span>
159 "Helena 0.8.0" is released and the
160 <a href="http://lambdadelta.info/implementation.html#lddl">λδ Digital Library</a>
166 <span class="date">June 2009.</span>
167 "Helena", a <a href="http://lambdadelta.info/implementation.html#helena">validator for λδ version 2</a>,
168 is available as a part of the <a href="http://helm.cs.unibo.it/">HELM</a> software.
173 <span class="date">September 2008.</span>
179 <span class="date">July 2008.</span>
180 <a href="http://lambdadelta.info/documentation.html#ldp5">First journal paper on λδ</a>
181 accepted for publication.
186 <span class="date">July 2008.</span>
187 First <a href="http://helm.cs.unibo.it/procedural/">procedural reconstruction</a>
188 for <a href="http://matita.cs.unibo.it/">Matita 0.5</a>
189 of the λδ version 1 for Coq 7.3.1.
194 <span class="date">June 2008.</span>
195 The <a href="http://lambdadelta.info/version_1.html#static">
196 HTML pages of the specification of λδ version 1 for Matita 0.5</a>
202 <span class="date">May 2008.</span>
203 The specification of λδ version 1 is dismissed.
208 <span class="date">March 2008.</span>
209 The specification of λδ version 2 is started with Coq 7.3.1 (false start).
214 <span class="date">September 2007.</span>
215 The <a href="http://lambdadelta.info/version_1.html#dynamic">
216 specification of λδ version 1 for Matita 0.4</a>
222 <span class="date">November 2006.</span>
223 <a href="http://lambdadelta.info/documentation.html#ldp3">λδ version 1</a>
229 <span class="date">December 2005.</span>
230 <a href="http://lambdadelta.info/documentation.html#ldt1">First communication on λδ</a>.
235 <span class="date">May 2004.</span>
236 The specification of <a href="http://lambdadelta.info/version_1.html">λδ version 1</a>
237 is started with Coq 7.3.1.
242 <div xmlns:ld="http://lambdadelta.info/" class="head2dx" id="visibility">Visibility <img class="icon37" alt="[spacer]" title="lambdadelta butterfly" src="http://lambdadelta.info/images/b4.png" />
244 <div xmlns:ld="http://lambdadelta.info/" class="text">
247 <span class="date">June 2014.</span>
248 The <a href="http://www.google.com/">Google</a>
249 search for "formal system lambda delta" gives
250 5 resources about λδ in the first 6 results.
255 <span class="date">June 2014.</span>
256 The <a href="http://www.yahoo.com/">Yahoo</a>
257 search for "formal system lambda delta" gives
258 4 resources about λδ in the first 5 results.
264 <img class="rule" alt="[Spacer]" title="lambdadelta rainbow rule" src="http://lambdadelta.info/images/rainbow.png" />
266 <div xmlns:ld="http://lambdadelta.info/" class="spacer">
269 <div xmlns:ld="http://lambdadelta.info/" class="spacer">
270 <a href="http://validator.w3.org/check?uri=referer">
271 <img class="w3c" alt="[Valid XHTML 1.1]" title="Valid XHTML 1.1" src="http://www.w3.org/Icons/valid-xhtml11-blue" />
273 <a href="http://jigsaw.w3.org/css-validator/check/referer">
274 <img class="w3c" alt="[Valid CSS level 2]" title="Valid CSS level 2" src="http://www.w3.org/Icons/valid-css2-blue" />
276 <a href="http://www.w3.org/XML/">
277 <img class="w3c" alt="[Generated from XML via XSL]" title="Generated from XML via XSL" src="http://lambdadelta.info/images/xml_xsl2.png" />
279 <a href="http://www.w3.org/Graphics/PNG/">
280 <img class="w3c" alt="[PNG used here]" title="PNG used here" src="http://lambdadelta.info/images/PNGnow2.png" />
282 <a href="http://www.anybrowser.org/campaign/">
283 <img class="w3c" alt="[Viewable with any browser]" title="Viewable with any browser" src="http://www.anybrowser.org/campaign/bvgraphics/abtfile.png" />
286 <div xmlns:ld="http://lambdadelta.info/" class="spacer">
289 <div xmlns:ld="http://lambdadelta.info/" class="spacer">Last update: Sun, 20 Jul 2014 11:29:55 +0200</div>