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5 <title>lambda_delta home page</title>
6 <meta content="Ferruccio Guidi" name="author">
7 <meta content="The formal system lambda_delta" name="description">
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16 <h1>The Formal System λδ (lambda_delta)<br>
18 <h2>Towards the unification of terms, types, environments and contexts</h2>
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26 <td style="vertical-align: top;">
28 <li><a href="index.html">Foreword</a></li>
31 <li><a href="news.html">News</a></li>
34 <li><a href="documentation.html">Papers</a></li>
41 <td style="vertical-align: top; text-align: left;">
42 <h3 style="text-align: right;">Computer-checked formal
43 specifications <img style="width: 37px; height: 37px;"
44 alt="[Butterfly]" title="Butterfly" src="download/b9.png"></h3>
45 <span style="font-weight: bold;">Resource
46 1</span> below provides for the statically generated <span
47 style="font-weight: bold;">natural language representation</span> of
48 λδ meta-theory (faster rendering w.r.t. resource 2 below).<br>
49 <span style="font-weight: bold;">Resource 2</span> below provides
50 for the dynamically generated <span style="font-weight: bold;">natural
51 language representation</span> of
52 λδ meta-theory (powered by the <a href="http://helm.cs.unibo.it/">HELM</a>
53 rendering engine).<br>
54 Remarkably, λδ was born and developed in the digital format of <span
55 style="font-weight: bold;">resource 3</span> below, which is not the
56 formal counterpart of some informal material previously written on
57 paper (as it happens for most currently digitalized Mathematics).<br>
59 <li><a name="static"></a>F. Guidi: <a
60 style="font-style: italic;" href="static/matita/lambda_delta/">lambda_delta</a>
61 (revised <span style="font-weight: bold;">2011-09</span>). Formal
62 specification with the proof assistant <a
63 href="http://matita.cs.unibo.it/">Matita</a> 0.5 (HTML pages generated
64 by the <a href="http://helm.cs.unibo.it/">HELM</a>
66 Here are the most relevant theorems proved in the formal specification:
69 href="static/matita/lambda_delta/Basic_1/pr3/pr3/pr3_confluence.con.html">Confluence
71 reduction</a> (Church-Rosser property).</li>
73 href="static/matita/lambda_delta/Basic_1/ty3/props/ty3_correct.con.html">Correctness
77 href="static/matita/lambda_delta/Basic_1/ty3/props/ty3_unique.con.html">Uniqueness
85 href="static/matita/lambda_delta/Basic_1/ty3/pr3/ty3_sred_pr3.con.html">Subject
92 href="static/matita/lambda_delta/Basic_1/ty3/arity_props/ty3_sn3.con.html">Strong
99 href="static/matita/lambda_delta/Basic_1/ty3/dec/ty3_inference.con.html">Decidability
109 <li><a name="dynamic"></a>F. Guidi: <a
110 style="font-style: italic;"
111 href="http://mowgli.cs.unibo.it:58080/apply?keys=RT&xmluri=http://helm.cs.unibo.it/helm//html/folder/index.html&prop.media-type=text/html&param.thmedia-type=text/html&param.thkeys=T1%2CT2%2CL%2CE&param.embedkeys=d_c%2CTC1%2CHC2%2CL&param.thencoding=UTF-8&prop.encoding=UTF-8&prop.doctype-public=-//W3C//DTD%20XHTML%201.0%20Transitional//EN&param.doctype-public=-//W3C//DTD%20XHTML%201.0%20Transitional//EN&param.encoding=UTF-8&param.media-type=text/html&param.keys=d_c%2CC1%2CHC2%2CL&profile=default&param.profile=default&param.CICURI=theory:/matita/lambda_delta/">lambda_delta</a>
112 (revised <span style="font-weight: bold;">2011-09</span>). Formal
113 specification with the proof assistant <a
114 href="http://matita.cs.unibo.it/">Matita</a> 0.5 (<a
115 href="http://helm.cs.unibo.it/">HELM</a> directory).<br>
118 <li><a name="source"></a>F. Guidi: <a
119 href="download/lambda_delta_1.tar.gz"><span
120 style="font-style: italic;">lambda_delta_1</span></a> (revised <span
121 style="font-weight: bold;">2011-09</span>).
122 Formal specification with the proof assistant <span
123 style="font-weight: bold;">Coq 7.3.1</span> (source
124 proof scripts). <a href="#bibtex">BibTeX entry</a>.<br>
127 <h3 style="text-align: right;">Tools <img
128 style="width: 37px; height: 37px;" alt="[Butterfly]" title="Butterfly"
129 src="download/b5.png"></h3>
130 <a name="lddl"></a><img style="width: 32px; height: 32px;"
131 alt="[Crux Logo]" title="The Crux" src="download/crux_32.png"><span
132 style="font-weight: bold;"> </span>The <span
133 style="font-weight: bold;"><span style="text-decoration: underline;">λδ
136 (LDDL)</span></span> is part of <a href="http://helm.cs.unibo.it/">HELM</a>
137 and contains a set of
138 resources expressed in λδ.<br>
140 <li><span style="font-weight: bold;">Contents:</span> Landau's "<span
141 style="font-style: italic;">Grundlagen der Analysis</span>" (from
142 Jutting's specification in <a href="http://www.win.tue.nl/automath/">Automath</a>).<br>
143 <span style="font-weight: bold;"></span></li>
146 <li><span style="font-weight: bold;">Access:</span> <a
147 href="static/lddl/">static pages</a> (updated <span
148 style="font-weight: bold;">2011-09</span>), <a
149 href="download/lddl.tar.bz2">data set</a> (updated <span
150 style="font-weight: bold;">2011-09</span>), <a
151 href="http://lambda-delta.info/xml">HELM server URL</a>
152 (updated <span style="font-weight: bold;">2011-09</span>).</li>
155 <li><span style="font-weight: bold;">Examples:</span> <a
156 href="static/lddl/brg_si/grundlagen/l/e/st/eq/landau/n/rt/rp/r/c/8283/t234.ld.html">Grundlagen's
158 "t234"</a> (in "basic_rg" λδ), <a
159 href="static/lddl/crg_si/grundlagen/l/e/st/eq/landau/n/rt/rp/r/c/8283/t234.ld.html">Grundlagen's
161 "t234"</a> (in "complete_rg" λδ).<br>
165 <a name="helena"></a><span style="font-weight: bold;"><img
166 style="width: 32px; height: 32px;" alt="[Helena Logo]" title="Helena"
167 src="download/helena_32.png"> <span
168 style="text-decoration: underline;">Helena</span></span> is a λδ
170 implemented in <a href="http://caml.inria.fr/">Caml</a> as a part of
171 the <a href="http://helm.cs.unibo.it/">HELM</a> software, meant for
172 testing the stable features of the calculus as well as the unstable
174 The processor source code is available in the directory <a
175 href="http://helm.cs.unibo.it/websvn/listing.php?repname=helm&path=%2Ftrunk%2Fhelm%2Fsoftware%2Fhelena%2F&rev=0&sc=0">/trunk/helm/software/helena/</a>
176 of the <a href="http://helm.cs.unibo.it/software/index.html">HELM Svn
177 repository</a>. The Svn revisions containing the stable versions
178 of Helena are indicated below. <br>
180 <li><span style="font-weight: bold;">Version 0.8.1 (2010-11).</span>
181 Exploits a subset of "complete_rg" λδ as the intermediate language.
182 Features importation from ".hln" files containing λδ textual syntax.
183 The overall validation speed of the "<span style="font-style: italic;">Grundlagen
185 Analysis</span>" increases of 22% with respect to version 0.8.0. [Svn
186 revision: 11032] (<a href="download/helena_0.8.1.tar.gz">archived
189 <li><span style="font-weight: bold;">2009-12.</span> Helena
190 appears in F. Wiedijk's <a
191 href="http://www.cs.ru.nl/%7Efreek/digimath/index.html#helena">index of
192 computer math systems</a>.</li>
197 <li><a style="font-weight: bold;"
198 href="documentation.html#ublcs-2009-16">Version 0.8.0</a><span
199 style="font-weight: bold;"> (2009-09).</span> Supports
200 "basic_rg" λδ with naive implementation of impredicative sort
202 importation from <a href="http://www.win.tue.nl/automath/">Automath</a>
203 and exportation to <a href="http://www.w3.org/XML/">XML</a>. [Svn
204 revision: 10304] (<a href="download/helena_0.8.0.tar.gz">archived
207 <li><span style="font-weight: bold;">2009-09.</span>
208 Jutting's specification of Landau's "<span style="font-style: italic;">Grundlagen
210 Analysis</span>" enters λδ Digital Library.<br>
211 <span style="font-weight: bold;"></span></li>
212 <li><span style="font-weight: bold;">2009-06.</span>
213 Jutting's specification of Landau's "<span style="font-style: italic;">Grundlagen
216 successfully processed, enabling sort inclusion<span
217 style="font-weight: bold;"></span>.</li>
221 <h3 style="text-align: right;">Other resources <img
222 style="width: 37px; height: 37px;" alt="[Butterfly]" title="Butterfly"
223 src="download/b4.png"></h3>
225 <li><a name="bibtex"></a>A
226 BibTeX database of λδ documentation: <a
227 href="download/lambda_delta.bib"><span style="font-style: italic;">lambda_delta.bib</span></a>,
230 <a style="font-style: italic;"
231 href="download/lambda_delta.txt">lambda_delta.txt</a> (revised <span
232 style="font-weight: bold;">2011-09</span>).</li>
235 <li>A <a href="http://www.jedsoft.org/jed/">Jed mode</a> for
236 editing ".hln" files (containing λδ textual syntax): <a
237 style="font-style: italic;" href="download/helena.sl">helena.sl</a>
238 (revised <span style="font-weight: bold;">2010-11</span>).</li>
241 <li>A <a href="http://www.jedsoft.org/jed/">Jed mode</a> for
242 editing ".aut" files (containing <a
243 href="http://www.win.tue.nl/automath/">Automath</a> textual syntax): <a
244 style="font-style: italic;" href="download/automath.sl">automath.sl</a>
245 (revised <span style="font-weight: bold;">2008-07</span>).</li>
248 <li>A logo for "basic" λδ: <a href="download/bld.pdf"><span
249 style="font-style: italic;">bld.pdf</span></a> (revised <span
250 style="font-weight: bold;">2008-07</span>).<br>
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269 src="download/PNGnow2.png"><br>
271 Last update 2011-09-09 by <a href="http://www.cs.unibo.it/%7Efguidi/">Ferruccio