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The Formal Systems of the λδ (\lambda\delta) Family
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documentation implementation
foreword milestones version 2 (background - core - applications)
version 2 helena Open Symbolic Notation (OSN)
citations visibility version 1 (background - core) (static HELM directory) version 1 library (static LDDL directory)
Computer-checked formal specifications [butterfly]
The systems of the λδ family are developed as machine-checked digital specifications, and are listed in the next table, which includes the major milestones.
The life cycle of a specification consists of four periods. Alpha: the definitions are designed and the major propositions are proved, then the calculus is announced with a presentation. Beta: major changes and additions may occur before the calculus is released on paper. Gamma: subsequent improvements occur until the specification is completed or superseded, while major changes and additions are announced and reported on paper. Delta: after its conclusion, the specification is modified just for maintenance.
version name stage developed with started announced released concluded references
Version 3 "basic_3" J3a
Version 2 "basic_2" "A2" Matita 0.99.3 October 2015


"A1" Matita 0.99.2 April 2011 June 2014 October 2014 August 2015 V2a R2c
Abandoned Coq 7.3.1 March 2008 February 2011
Version 1 "basic_1" Coq 7.3.1 May 2004 December 2005 November 2006 May 2008 V1a J1a
Informational pages on the specifications are provided.
[butterfly] λδ version 3 (proposed)
The formal specification of λδ version 3 is forthcoming.
[butterfly] λδ version 2 (active)
The formal specification of λδ version 2 is available in the following formats:
Informational pages on the parts of the specification: Background, Core, Applications.
[butterfly] λδ version 1 (superseded)
The formal specification of λδ version 1 is available in the following formats:
Informational pages on the parts of the specification: Background, Core.
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Last update: Wed, 17 Jan 2018 20:27:12 +0100