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 Systems of the λδ (\lambda\delta) Family</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 capitalize italic sky">
34 <a href="http://lambdadelta.info/index.html">home</a>
36 <td class="snns capitalize italic magenta">
37 <a href="http://lambdadelta.info/news.html">news</a>
39 <td class="snns capitalize italic white">
40 <a href="http://lambdadelta.info/specification.html">specification</a>
42 <td class="snnn capitalize italic white">
45 <td class="snnn capitalize italic white">
48 <td class="snns capitalize italic orange">
49 <a href="http://lambdadelta.info/documentation.html">documentation</a>
51 <td class="snns capitalize italic green">
52 <a href="http://lambdadelta.info/implementation.html">implementation</a>
54 <td class="ssnn capitalize italic green">
59 <td class="snns capitalize sky">
60 <a href="http://lambdadelta.info/index.html#foreword">foreword</a>
62 <td class="snns capitalize magenta">
63 <a href="http://lambdadelta.info/news.html#milestones">milestones</a>
65 <td class="snns capitalize white">
66 <a href="http://lambdadelta.info/specification.html#v2">version 2</a>
68 <td class="snnn capitalize white">(<a href="http://lambdadelta.info/ground_2.html">background</a> - <a href="http://lambdadelta.info/basic_2.html">core</a> - <a href="http://lambdadelta.info/apps_2.html">applications</a>)</td>
69 <td class="snnn capitalize white">
72 <td class="snns capitalize orange">
73 <a href="http://lambdadelta.info/documentation.html#v2">version 2</a>
75 <td class="snns capitalize green">
76 <a href="http://lambdadelta.info/implementation.html#lddl">library</a>
78 <td class="ssnn capitalize green">(<a href="http://lambdadelta.info/static/lddl/">static LDDL directory</a>)</td>
81 <td class="snss capitalize sky">
82 <a href="http://lambdadelta.info/index.html#citations">citations</a>
84 <td class="snss capitalize magenta">
85 <a href="http://lambdadelta.info/news.html#visibility">visibility</a>
87 <td class="snss capitalize white">
88 <a href="http://lambdadelta.info/specification.html#v1">version 1</a>
90 <td class="snsn capitalize white">(<a href="http://lambdadelta.info/ground_1.html">background</a> - <a href="http://lambdadelta.info/basic_1.html">core</a>)</td>
91 <td class="snsn capitalize white">(<a href="http://lambdadelta.info/static/matita/lambdadelta/">static HELM directory</a>)</td>
92 <td class="snss capitalize orange">
93 <a href="http://lambdadelta.info/documentation.html#v1">version 1</a>
95 <td class="snss capitalize green">
96 <a href="http://lambdadelta.info/implementation.html#helena">helena</a>
98 <td class="sssn capitalize green">
105 <!-- ===================================================================== -->
106 <div xmlns:ld="http://lambdadelta.info/" class="head2dx" id="milestones">Milestones <img class="icon37" alt="[spacer]" title="lambdadelta butterfly" src="http://lambdadelta.info/images/b3.png" />
108 <ul xmlns:ld="http://lambdadelta.info/">
110 <span class="emph gamma">December 2015.</span>
111 <a href="http://lambdadelta.info/implementation.html#v3">"Helena 0.8.3"</a> is released.
114 <ul xmlns:ld="http://lambdadelta.info/">
116 <span class="emph delta">August 2015.</span>
117 The specification of λδ version 2A1 is concluded.
120 <ul xmlns:ld="http://lambdadelta.info/">
122 <span class="emph gamma">June 2015.</span>
123 The corrected specification of Landau's "Grundlagen der Analysis"
124 is validated in a λProlog implementation of λδ version 3.
127 <ul xmlns:ld="http://lambdadelta.info/">
129 <span class="emph delta">March 2015.</span>
130 The specification of λδ version 1 is validated by
131 <a href="http://matita.cs.unibo.it/">Matita 0.99.2</a>.
134 <ul xmlns:ld="http://lambdadelta.info/">
136 <span class="emph gamma">February 2015.</span>
137 <a href="http://lambdadelta.info/implementation.html#v2">"Helena 0.8.2"</a> is updated.
140 The translated specification of Landau's "Grundlagen der Analysis"
141 is validated in CC by <a href="http://coq.inria.fr/">Coq 8.4.3</a>.
146 <ul xmlns:ld="http://lambdadelta.info/">
148 <span class="emph delta">January 2015.</span>
149 The specification of <a href="http://lambdadelta.info/specification.html#v1">λδ version 1</a>
150 is updated with backports from the abandoned specification of λδ version 2.
153 <ul xmlns:ld="http://lambdadelta.info/">
155 <span class="emph gamma">December 2014.</span>
156 <a href="http://lambdadelta.info/implementation.html#v2">"Helena 0.8.2"</a> is released.
159 The corrected specification of Landau's "Grundlagen der Analysis"
160 is validated in λδ version 3.
165 <ul xmlns:ld="http://lambdadelta.info/">
167 <span class="emph gamma">October 2014.</span>
168 <a href="http://lambdadelta.info/documentation.html#ldJ2a">λδ version 2A1</a>
172 <ul xmlns:ld="http://lambdadelta.info/">
174 <span class="emph beta">July 2014.</span>
175 A new version of this site is online.
178 <ul xmlns:ld="http://lambdadelta.info/">
180 <span class="emph beta">June 2014.</span>
181 <a href="http://lambdadelta.info/documentation.html#ldP2c">First communication on λδ version 2.</a>
184 <ul xmlns:ld="http://lambdadelta.info/">
186 <span class="emph alpha">December 2012.</span>
187 The character "_" is removed from the denomination "lambda_delta":
190 The denomination "\lambda\delta" is used in λδ-related texts.
193 The denomination "lambdadelta" is used in λδ-related identifiers.
196 Permanent λδ URL acquired:
197 <a href="http://lambdadelta.info/">http://lambdadelta.info/</a>
198 (pointing at this site).
203 <ul xmlns:ld="http://lambdadelta.info/">
205 <span class="emph alpha">September 2011.</span>
206 The denomination "lambda-delta" changes to "lambda_delta":
209 The character "-" is reserved in λδ textual syntax
210 (recognized by "Helena 0.8.1").
213 Eventually, the occurrences of the character "-"
214 will be replaced by "_" in all λδ-related identifiers.
217 In particular, this refactoring involves file names and path names.
222 <ul xmlns:ld="http://lambdadelta.info/">
224 <span class="emph alpha">April 2011.</span>
225 The specification of <a href="http://lambdadelta.info/specification.html#v2">λδ version 2</a>
226 and related topics is restarted in
227 <a href="http://matita.cs.unibo.it/">Matita 0.5</a>.
230 <ul xmlns:ld="http://lambdadelta.info/">
232 <span class="emph delta">February 2011.</span>
233 The specification of λδ version 2 with Coq 7.3.1 is abandoned.
236 <ul xmlns:ld="http://lambdadelta.info/">
238 <span class="emph alpha">December 2010.</span>
239 Transient λδ URL acquired: http://lambda-delta.info/ (expires on December 2012).
242 <ul xmlns:ld="http://lambdadelta.info/">
244 <span class="emph beta">November 2010.</span>
245 <a href="http://lambdadelta.info/implementation.html#v1">"Helena 0.8.1"</a> is released.
248 <ul xmlns:ld="http://lambdadelta.info/">
250 <span class="emph beta">September 2009.</span>
251 <a href="http://lambdadelta.info/implementation.html#v0">"Helena 0.8.0"</a> is released and the
252 <a href="http://lambdadelta.info/implementation.html#lddl">λδ Digital Library</a> is started.
255 <ul xmlns:ld="http://lambdadelta.info/">
257 <span class="emph alpha">June 2009.</span>
258 "Helena", a <a href="http://lambdadelta.info/implementation.html#helena">validator for λδ version 2</a>,
259 is available as a part of the <a href="http://helm.cs.unibo.it/">HELM</a> software.
262 <ul xmlns:ld="http://lambdadelta.info/">
264 <span class="emph alpha">September 2008.</span>
268 <ul xmlns:ld="http://lambdadelta.info/">
270 <span class="emph delta">July 2008.</span>
271 <a href="http://lambdadelta.info/documentation.html#ldJ1a">First journal paper on λδ</a>
272 accepted for publication.
275 <ul xmlns:ld="http://lambdadelta.info/">
277 <span class="emph delta">July 2008.</span>
278 First <a href="http://helm.cs.unibo.it/procedural/">procedural reconstruction</a>
279 for <a href="http://matita.cs.unibo.it/">Matita 0.5</a>
280 of the λδ version 1 for Coq 7.3.1.
283 <ul xmlns:ld="http://lambdadelta.info/">
285 <span class="emph delta">June 2008.</span>
286 The <a href="http://lambdadelta.info/specification.html#static1">
287 HTML pages of the specification of λδ version 1 for Matita 0.5</a>
291 <ul xmlns:ld="http://lambdadelta.info/">
293 <span class="emph delta">May 2008.</span>
294 The specification of λδ version 1 is concluded.
297 <ul xmlns:ld="http://lambdadelta.info/">
299 <span class="emph alpha">March 2008.</span>
300 The specification of λδ version 2 is started with Coq 7.3.1 (false start).
303 <ul xmlns:ld="http://lambdadelta.info/">
305 <span class="emph gamma">September 2007.</span>
306 The <a href="http://lambdadelta.info/specification.html#dynamic1">
307 specification of λδ version 1 for Matita 0.4</a>
311 <ul xmlns:ld="http://lambdadelta.info/">
313 <span class="emph gamma">November 2006.</span>
314 <a href="http://lambdadelta.info/documentation.html#ldR1b">λδ version 1</a>
318 <ul xmlns:ld="http://lambdadelta.info/">
320 <span class="emph beta">December 2005.</span>
321 <a href="http://lambdadelta.info/documentation.html#ldP1a">First communication on λδ version 1</a>.
324 <ul xmlns:ld="http://lambdadelta.info/">
326 <span class="emph alpha">May 2004.</span>
327 The specification of <a href="http://lambdadelta.info/specification.html#v1">λδ version 1</a>
328 is started with Coq 7.3.1.
331 <!-- ===================================================================== -->
332 <div xmlns:ld="http://lambdadelta.info/" class="head2dx" id="visibility">Visibility <img class="icon37" alt="[spacer]" title="lambdadelta butterfly" src="http://lambdadelta.info/images/b3.png" />
334 <ul xmlns:ld="http://lambdadelta.info/">
336 <span class="emph alpha">June 2014.</span>
337 The <a href="http://www.google.com/">Google</a>
338 search for "formal system lambda delta" gives
339 5 resources about the λδ family in the first 6 results.
342 <ul xmlns:ld="http://lambdadelta.info/">
344 <span class="emph alpha">June 2014.</span>
345 The <a href="http://www.yahoo.com/">Yahoo</a>
346 search for "formal system lambda delta" gives
347 4 resources about the λδ family in the first 5 results.
351 <img class="rule" alt="[Spacer]" title="lambdadelta rainbow rule" src="http://lambdadelta.info/images/rainbow.png" />
353 <div xmlns:ld="http://lambdadelta.info/" class="spacer">
356 <div xmlns:ld="http://lambdadelta.info/" class="spacer">
357 <a href="http://validator.w3.org/check?uri=referer">
358 <img class="w3c" alt="[Valid XHTML 1.1]" title="Valid XHTML 1.1" src="http://www.w3.org/Icons/valid-xhtml11-blue" />
360 <a href="http://jigsaw.w3.org/css-validator/check/referer">
361 <img class="w3c" alt="[Valid CSS level 2]" title="Valid CSS level 2" src="http://www.w3.org/Icons/valid-css2-blue" />
363 <a href="http://www.w3.org/XML/">
364 <img class="w3c" alt="[Generated from XML via XSL]" title="Generated from XML via XSL" src="http://lambdadelta.info/images/xml_xsl2.png" />
366 <a href="http://www.w3.org/Graphics/PNG/">
367 <img class="w3c" alt="[PNG used here]" title="PNG used here" src="http://lambdadelta.info/images/PNGnow2.png" />
369 <a href="http://www.anybrowser.org/campaign/">
370 <img class="w3c" alt="[Viewable with any browser]" title="Viewable with any browser" src="http://www.anybrowser.org/campaign/bvgraphics/abtfile.png" />
373 <div xmlns:ld="http://lambdadelta.info/" class="spacer">
376 <div xmlns:ld="http://lambdadelta.info/" class="spacer">Last update: Wed, 30 Dec 2015 15:33:02 +0100</div>