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="[\lambda\delta home]" title="\lambda\delta 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="\lambda\delta 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/home.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/home.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#helena">helena</a>
78 <td class="ssnn capitalize green">
79 <a href="http://lambdadelta.info/osn/">Open Symbolic Notation (OSN)</a>
83 <td class="snss capitalize sky">
84 <a href="http://lambdadelta.info/home.html#citations">citations</a>
86 <td class="snss capitalize magenta">
87 <a href="http://lambdadelta.info/news.html#visibility">visibility</a>
89 <td class="snss capitalize white">
90 <a href="http://lambdadelta.info/specification.html#v1">version 1</a>
92 <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>
93 <td class="snsn capitalize white">(<a href="http://lambdadelta.info/static/matita/lambdadelta/">static HELM directory</a>)</td>
94 <td class="snss capitalize orange">
95 <a href="http://lambdadelta.info/documentation.html#v1">version 1</a>
97 <td class="snss capitalize green">
98 <a href="http://lambdadelta.info/implementation.html#lddl">library</a>
100 <td class="sssn capitalize green">(<a href="http://lambdadelta.info/static/lddl/">static LDDL directory</a>)</td>
105 <!-- ===================================================================== -->
106 <div xmlns:ld="http://lambdadelta.info/" class="head2dx" id="milestones">Milestones <img class="icon37" alt="[butterfly]" title="\lambda\delta butterfly" src="http://lambdadelta.info/images/b3.png" />
108 <ul xmlns:ld="http://lambdadelta.info/">
110 <span class="emph alpha">December 2015.</span>
111 <a href="http://lambdadelta.info/documentation.html#ldJ3a">Second journal paper on λδ</a>
112 accepted for publication.
115 <ul xmlns:ld="http://lambdadelta.info/">
117 <span class="emph gamma">December 2015.</span>
118 <a href="http://lambdadelta.info/implementation.html#v3">"Helena 0.8.3"</a> is released.
121 <ul xmlns:ld="http://lambdadelta.info/">
123 <span class="emph delta">August 2015.</span>
124 The specification of λδ version 2A1 is concluded.
127 <ul xmlns:ld="http://lambdadelta.info/">
129 <span class="emph gamma">June 2015.</span>
130 The corrected specification of Landau's "Grundlagen der Analysis"
131 is validated in a λProlog implementation of λδ version 3.
134 <ul xmlns:ld="http://lambdadelta.info/">
136 <span class="emph delta">March 2015.</span>
137 The specification of λδ version 1 is validated by
138 <a href="http://matita.cs.unibo.it/">Matita 0.99.2</a>.
141 <ul xmlns:ld="http://lambdadelta.info/">
143 <span class="emph gamma">February 2015.</span>
144 <a href="http://lambdadelta.info/implementation.html#v2">"Helena 0.8.2"</a> is updated.
147 The translated specification of Landau's "Grundlagen der Analysis"
148 is validated in CC by <a href="http://coq.inria.fr/">Coq 8.4.3</a>.
153 <ul xmlns:ld="http://lambdadelta.info/">
155 <span class="emph delta">January 2015.</span>
156 The specification of <a href="http://lambdadelta.info/specification.html#v1">λδ version 1</a>
157 is updated with backports from the abandoned specification of λδ version 2.
160 <ul xmlns:ld="http://lambdadelta.info/">
162 <span class="emph gamma">December 2014.</span>
163 <a href="http://lambdadelta.info/implementation.html#v2">"Helena 0.8.2"</a> is released.
166 The corrected specification of Landau's "Grundlagen der Analysis"
167 is validated in λδ version 3.
172 <ul xmlns:ld="http://lambdadelta.info/">
174 <span class="emph gamma">October 2014.</span>
175 <a href="http://lambdadelta.info/documentation.html#ldJ2a">λδ version 2A1</a>
179 <ul xmlns:ld="http://lambdadelta.info/">
181 <span class="emph beta">July 2014.</span>
182 A new version of this site is online.
185 <ul xmlns:ld="http://lambdadelta.info/">
187 <span class="emph beta">June 2014.</span>
188 <a href="http://lambdadelta.info/documentation.html#ldP2c">First communication on λδ version 2.</a>
191 <ul xmlns:ld="http://lambdadelta.info/">
193 <span class="emph alpha">December 2012.</span>
194 The character "_" is removed from the denomination "lambda_delta":
197 The denomination "\lambda\delta" is used in λδ-related texts.
200 The denomination "lambdadelta" is used in λδ-related identifiers.
203 Permanent λδ URL acquired:
204 <a href="http://lambdadelta.info/">http://lambdadelta.info/</a>
205 (pointing at this site).
210 <ul xmlns:ld="http://lambdadelta.info/">
212 <span class="emph alpha">September 2011.</span>
213 The denomination "lambda-delta" changes to "lambda_delta":
216 The character "-" is reserved in λδ textual syntax
217 (recognized by "Helena 0.8.1").
220 Eventually, the occurrences of the character "-"
221 will be replaced by "_" in all λδ-related identifiers.
224 In particular, this refactoring involves file names and path names.
229 <ul xmlns:ld="http://lambdadelta.info/">
231 <span class="emph alpha">April 2011.</span>
232 The specification of <a href="http://lambdadelta.info/specification.html#v2">λδ version 2</a>
233 and related topics is restarted in
234 <a href="http://matita.cs.unibo.it/">Matita 0.5</a>.
237 <ul xmlns:ld="http://lambdadelta.info/">
239 <span class="emph delta">February 2011.</span>
240 The specification of λδ version 2 with Coq 7.3.1 is abandoned.
243 <ul xmlns:ld="http://lambdadelta.info/">
245 <span class="emph alpha">December 2010.</span>
246 Transient λδ URL acquired: http://lambda-delta.info/ (expires on December 2012).
249 <ul xmlns:ld="http://lambdadelta.info/">
251 <span class="emph beta">November 2010.</span>
252 <a href="http://lambdadelta.info/implementation.html#v1">"Helena 0.8.1"</a> is released.
255 <ul xmlns:ld="http://lambdadelta.info/">
257 <span class="emph beta">September 2009.</span>
258 <a href="http://lambdadelta.info/implementation.html#v0">"Helena 0.8.0"</a> is released and the
259 <a href="http://lambdadelta.info/implementation.html#lddl">λδ Digital Library</a> is started.
262 <ul xmlns:ld="http://lambdadelta.info/">
264 <span class="emph alpha">June 2009.</span>
265 "Helena", a <a href="http://lambdadelta.info/implementation.html#helena">validator for λδ version 2</a>,
266 is available as a part of the <a href="http://helm.cs.unibo.it/">HELM</a> software.
269 <ul xmlns:ld="http://lambdadelta.info/">
271 <span class="emph alpha">September 2008.</span>
275 <ul xmlns:ld="http://lambdadelta.info/">
277 <span class="emph delta">July 2008.</span>
278 <a href="http://lambdadelta.info/documentation.html#ldJ1a">First journal paper on λδ</a>
279 accepted for publication.
282 <ul xmlns:ld="http://lambdadelta.info/">
284 <span class="emph delta">July 2008.</span>
285 First <a href="http://helm.cs.unibo.it/procedural/">procedural reconstruction</a>
286 for <a href="http://matita.cs.unibo.it/">Matita 0.5</a>
287 of the λδ version 1 for Coq 7.3.1.
290 <ul xmlns:ld="http://lambdadelta.info/">
292 <span class="emph delta">June 2008.</span>
293 The <a href="http://lambdadelta.info/specification.html#static1">
294 HTML pages of the specification of λδ version 1 for Matita 0.5</a>
298 <ul xmlns:ld="http://lambdadelta.info/">
300 <span class="emph delta">May 2008.</span>
301 The specification of λδ version 1 is concluded.
304 <ul xmlns:ld="http://lambdadelta.info/">
306 <span class="emph alpha">March 2008.</span>
307 The specification of λδ version 2 is started with Coq 7.3.1 (false start).
310 <ul xmlns:ld="http://lambdadelta.info/">
312 <span class="emph gamma">September 2007.</span>
313 The <a href="http://lambdadelta.info/specification.html#dynamic1">
314 specification of λδ version 1 for Matita 0.4</a>
318 <ul xmlns:ld="http://lambdadelta.info/">
320 <span class="emph gamma">November 2006.</span>
321 <a href="http://lambdadelta.info/documentation.html#ldR1b">λδ version 1</a>
325 <ul xmlns:ld="http://lambdadelta.info/">
327 <span class="emph beta">December 2005.</span>
328 <a href="http://lambdadelta.info/documentation.html#ldP1a">First communication on λδ version 1</a>.
331 <ul xmlns:ld="http://lambdadelta.info/">
333 <span class="emph alpha">May 2004.</span>
334 The specification of <a href="http://lambdadelta.info/specification.html#v1">λδ version 1</a>
335 is started with Coq 7.3.1.
338 <!-- ===================================================================== -->
339 <div xmlns:ld="http://lambdadelta.info/" class="head2dx" id="visibility">Visibility <img class="icon37" alt="[butterfly]" title="\lambda\delta butterfly" src="http://lambdadelta.info/images/b3.png" />
341 <ul xmlns:ld="http://lambdadelta.info/">
343 <span class="emph alpha">June 2014.</span>
344 The <a href="http://www.google.com/">Google</a>
345 search for "formal system lambda delta" gives
346 5 resources about the λδ family in the first 6 results.
349 <ul xmlns:ld="http://lambdadelta.info/">
351 <span class="emph alpha">June 2014.</span>
352 The <a href="http://www.yahoo.com/">Yahoo</a>
353 search for "formal system lambda delta" gives
354 4 resources about the λδ family in the first 5 results.
358 <img class="rule" alt="[Spacer]" title="\lambda\delta rainbow rule" src="http://lambdadelta.info/images/rainbow.png" />
360 <div xmlns:ld="http://lambdadelta.info/" class="spacer">
363 <div xmlns:ld="http://lambdadelta.info/" class="spacer">
364 <a href="http://validator.w3.org/check?uri=referer">
365 <img class="w3c" alt="[Valid XHTML 1.1]" title="Valid XHTML 1.1" src="http://www.w3.org/Icons/valid-xhtml11-blue" />
367 <a href="http://jigsaw.w3.org/css-validator/check/referer">
368 <img class="w3c" alt="[Valid CSS level 2]" title="Valid CSS level 2" src="http://www.w3.org/Icons/valid-css2-blue" />
370 <a href="http://www.w3.org/XML/">
371 <img class="w3c" alt="[Generated from XML via XSL]" title="Generated from XML via XSL" src="http://lambdadelta.info/images/xml_xsl2.png" />
373 <a href="http://www.w3.org/Graphics/PNG/">
374 <img class="w3c" alt="[PNG used here]" title="PNG used here" src="http://lambdadelta.info/images/PNGnow2.png" />
376 <a href="http://www.anybrowser.org/campaign/">
377 <img class="w3c" alt="[Viewable with any browser]" title="Viewable with any browser" src="http://www.anybrowser.org/campaign/bvgraphics/abtfile.png" />
380 <div xmlns:ld="http://lambdadelta.info/" class="spacer">
383 <div xmlns:ld="http://lambdadelta.info/" class="spacer">Last update: Sun, 22 Jan 2017 20:42:51 +0100</div>