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 <section15 name="specifications">Computer-checked formal specifications</section15>
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24 subsequent improvements occur until the specification is completed or superseded,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"/>
32 Informational pages on the specifications are provided.
35 <notice class="alpha" notice="Notice on displayed numerical acounts:"/>
36 nodes are counted according to the "intrinsic complexity measure"
37 [F. Guidi: "Procedural Representation of CIC Proof Terms"
38 Journal of Automated Reasoning 44(1-2), Springer (February 2010), pp. 53-78].
41 <notice class="alpha" notice="Notice on displayed logical structures:"/>
42 from the logical standpoint, the source scripts are grouped in "planes"
43 and these are grouped in "components";
44 the notation for the relations or functions
45 introduced in each script, is shown in parentheses (? are placeholders).
48 <!-- VERSION 2 =========================================================== -->
50 <subsection name="v2"><version2-icon/>λδ version 2 (active)</subsection>
52 The formal specification of λδ version 2
53 is available in the following formats:
56 <topitem name="source2">
58 <rlink to="download/lambdadelta_2.tar.gz">lambdadelta_2 for Matita 0.99.2</rlink>
59 (revised <notice class="gamma" notice="2014-10"/>).
63 The scripts are grouped in directories, first by part, then by component.
66 <notice class="alpha" notice="Notice:"/>
67 the scripts are checked by the latest version of Matita from
68 <link to="http://matita.cs.unibo.it/download.shtml">HELM Subversion repository</link>
69 at path <trunk/matita/>.
74 Informational pages on the parts of the specification:
75 <rlink to="ground_2.html">Background</rlink>,
76 <rlink to="basic_2.html">Core</rlink>,
77 <rlink to="apps_2.html">Applications</rlink>.
80 <!-- VERSION 1 =========================================================== -->
82 <subsection name="v1"><version1-icon/>λδ version 1 (superseded)</subsection>
84 The formal specification of λδ version 1
85 is available in the following formats:
88 <topitem name="source1">
90 <rlink to="download/lambdadelta_1.tar.gz">lambdadelta_1 for Coq 7.3.1</rlink>
91 (revised <notice class="delta" notice="2015-01"/>).
94 <notice class="delta" notice="2015 January 15."/>
95 17 new lemmas and former lemma "eq_nat_dec" renamed as "nat_dec_neg".
99 The scripts are grouped in directories, one for each part.
103 <topitem name="static1">
104 <rlink to="static/matita/lambdadelta/">lambdadelta_1 for Matita 0.5</rlink>
105 (revised <notice class="delta" notice="2011-09"/>).
106 Static HTML pages generated by the <link to="http://helm.cs.unibo.it/">HELM</link> rendering engine.
108 <rlink to="static/matita/lambdadelta/basic_1/pr3/pr3/pr3_confluence.con.html">
109 Confluence of reduction</rlink>
110 (Church-Rosser property).
112 <rlink to="static/matita/lambdadelta/basic_1/ty3/props/ty3_correct.con.html">
113 Correctness of types</rlink>.
115 <rlink to="static/matita/lambdadelta/basic_1/ty3/props/ty3_unique.con.html">
116 Uniqueness of types up to conversion</rlink>.
118 <rlink to="static/matita/lambdadelta/basic_1/ty3/pr3/ty3_sred_pr3.con.html">
119 Subject reduction of the type assignment</rlink>.
121 <rlink to="static/matita/lambdadelta/basic_1/ty3/arity_props/ty3_sn3.con.html">
122 Strong normalization of the typed terms</rlink>.
124 <rlink to="static/matita/lambdadelta/basic_1/ty3/dec/ty3_inference.con.html">
125 Decidability of the type inference problem</rlink>.
129 <topitem name="dynamic1">
130 <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/">
131 lambdadelta_1 for Matita 0.5</link>
132 (revised <notice class="delta" notice="2011-09"/>).
133 <link to="http://helm.cs.unibo.it/">HELM</link> directory.
134 <notice class="alpha" notice="Notice: the HELM rendering engine is offline."/>
138 Informational pages on the parts of the specification:
139 <rlink to="ground_1.html">Background</rlink>,
140 <rlink to="basic_1.html">Core</rlink>.