1 <?xml version="1.0" encoding="UTF-8"?>
3 <page xmlns="http://lambdadelta.info/"
4 description = "\lambda\delta home page"
5 title = "\lambda\delta home page"
6 head = "The Formal System λδ (\lambda\delta)"
8 <sitemap name="sitemap"/>
10 <section5 name="specifications">Computer-checked formal specifications</section5>
12 λδ is developed as a machine-checked digital specification.
13 It comes in several versions listed in the next table,
14 which includes the major milestones.
17 The life cycle of a specification consists of four periods.
18 <notice class="alpha" notice="Alpha:"/>
19 the definitions are designed and the major propositions are proved,
20 then the calculus is announced with a presentation.
21 <notice class="beta" notice="Beta:"/>
22 major changes and additions may occur before the calculus is released on paper.
23 <notice class="gamma" notice="Gamma:"/>
24 subsequent improvements occur until the specification is completed or superseded,
25 while major changes and additions are announced and reported on paper.
26 <notice class="delta" notice="Delta:"/>
27 after its conclusion, the specification is modified just for maintenance.
29 <table name="versions"/>
31 <!-- VERSION 2 =========================================================== -->
33 <subsection name="v2"><version2-icon/>λδ version 2 (active)</subsection>
35 The formal specification of λδ version 2
36 is available in the following formats:
39 <topitem name="source2">
41 <rlink to="download/lambdadelta_2.tar.gz">lambdadelta_2 for Matita 0.99.2</rlink>
42 (revised <notice class="gamma" notice="2014-10"/>).
46 The scripts are grouped in directories, first by part, then by component.
49 <notice class="alpha" notice="Notice:"/>
50 the scripts are checked by the latest version of Matita from
51 <link to="http://matita.cs.unibo.it/download.shtml">HELM Subversion repository</link>
52 at path <trunk/matita/>.
57 Informational pages on the parts of the specification:
58 <rlink to="ground_2.html">Background</rlink>,
59 <rlink to="basic_2.html">Core</rlink>,
60 <rlink to="apps_2.html">Applications</rlink>.
63 <notice class="alpha" notice="Notice on numerical acounts:"/>
64 nodes are counted according to the "intrinsic complexity measure"
65 [F. Guidi: "Procedural Representation of CIC Proof Terms"
66 Journal of Automated Reasoning 44(1-2), Springer (February 2010), pp. 53-78].
69 <notice class="alpha" notice="Notice on displayed logical structures:"/>
70 from the logical standpoint, the source scripts are grouped in "planes"
71 and these are grouped in "components";
72 the notation for the relations or functions
73 introduced in each script, is shown in parentheses (? are placeholders).
76 <!-- VERSION 1 =========================================================== -->
78 <subsection name="v1"><version1-icon/>λδ version 1 (superseded)</subsection>
80 The formal specification of λδ version 1
81 is available in the following formats:
84 <topitem name="source1">
86 <rlink to="download/lambdadelta_1.tar.gz">lambdadelta_1 for Coq 7.3.1</rlink>
87 (revised <notice class="delta" notice="2012-10"/>).
91 The scripts are grouped in directories, one for each part.
95 <topitem name="static1">
96 <rlink to="static/matita/lambdadelta/">lambdadelta_1 for Matita 0.5</rlink>
97 (revised <notice class="delta" notice="2011-09"/>).
98 Static HTML pages generated by the <link to="http://helm.cs.unibo.it/">HELM</link> rendering engine.
100 <rlink to="static/matita/lambdadelta/basic_1/pr3/pr3/pr3_confluence.con.html">
101 Confluence of reduction</rlink>
102 (Church-Rosser property).
104 <rlink to="static/matita/lambdadelta/basic_1/ty3/props/ty3_correct.con.html">
105 Correctness of types</rlink>.
107 <rlink to="static/matita/lambdadelta/basic_1/ty3/props/ty3_unique.con.html">
108 Uniqueness of types up to conversion</rlink>.
110 <rlink to="static/matita/lambdadelta/basic_1/ty3/pr3/ty3_sred_pr3.con.html">
111 Subject reduction of the type assignment</rlink>.
113 <rlink to="static/matita/lambdadelta/basic_1/ty3/arity_props/ty3_sn3.con.html">
114 Strong normalization of the typed terms</rlink>.
116 <rlink to="static/matita/lambdadelta/basic_1/ty3/dec/ty3_inference.con.html">
117 Decidability of the type inference problem</rlink>.
121 <topitem name="dynamic1">
122 <link to="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/lambdadelta/">
123 lambdadelta_1 for Matita 0.5</link>
124 (revised <notice class="delta" notice="2011-09"/>).
125 <link to="http://helm.cs.unibo.it/">HELM</link> directory.
126 <notice class="alpha" notice="Notice: the HELM rendering engine is offline."/>