# Gappa

> theorem prover

**Wikidata**: [Q104955762](https://www.wikidata.org/wiki/Q104955762)  
**Source**: https://4ort.xyz/entity/gappa

## Summary
Gappa is a theorem prover and proof assistant developed by the Institut National de Recherche en Informatique et en Automatique (INRIA). As free software, it allows users to freely run, study, change, and distribute it along with modified versions. It is available under both CeCILL and GNU General Public License version 2.0 licenses, with source code hosted on GitLab.

## Key Facts
- Gappa is a theorem prover, as per its Wikidata description
- Instance of: proof assistant; free software (sitelink_count: 120)
- Developer: Institut National de Recherche en Informatique et en Automatique
- License: CeCILL (references: https://gitlab.inria.fr/gappa/gappa/-/blob/master/COPYING); GNU General Public License, version 2.0 (references: https://gitlab.inria.fr/gappa/gappa/-/blob/master/COPYING.GPL)
- Version 1.0.0 released on 2013-07-14 (references: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.0.0)
- Version 1.1.0 released on 2013-12-20 (references: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.1.0)
- Version 1.1.1 released on 2014-03-25 (references: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.1.1)
- Version 1.1.2 released on 2014-10-14 (references: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.1.2)
- Version 1.2.0 released on 2015-05-19 (references: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.2.0)
- Version 1.2.1 released on 2016-01-26 (references: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.2.1)
- Version 1.2.2 released on 2016-06-22 (references: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.2.2)
- Version 1.3.0 released on 2016-07-20 (references: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.0)
- Version 1.3.1 released on 2016-11-25 (references: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.1)
- Version 1.3.2 released on 2017-01-09 (references: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.2)
- Version 1.3.3 released on 2018-07-18 (references: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.3)
- Version 1.3.4 released on 2019-03-01 (references: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.4)
- Preferred version: 1.3.5 released on 2019-03-24 (references: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.5)
- Website: http://gappa.gforge.inria.fr/ (language: English)
- Source code repository: https://gitlab.inria.fr/gappa/gappa (programming paradigm: GitLab; programming language: OCaml)
- Issue tracker: https://gitlab.inria.fr/gappa/gappa/-/issues
- Open Hub ID: gappa
- Repology project name: gappa-prover
- Copyright status: copyrighted

## FAQs
**What does Gappa do?**  
Gappa functions as a theorem prover and proof assistant. It falls under the category of free software, enabling users to run, study, change, and distribute it freely.

**Who develops Gappa and where can its code be found?**  
The Institut National de Recherche en Informatique et en Automatique (INRIA) develops Gappa. Its source code resides at https://gitlab.inria.fr/gappa/gappa, with issues tracked at https://gitlab.inria.fr/gappa/gappa/-/issues.

**What licenses cover Gappa?**  
Gappa uses the CeCILL license, detailed at https://gitlab.inria.fr/gappa/gappa/-/blob/master/COPYING. It also employs the GNU General Public License version 2.0, outlined at https://gitlab.inria.fr/gappa/gappa/-/blob/master/COPYING.GPL.

**What versions of Gappa exist and when were they released?**  
Releases span from 1.0.0 on 2013-07-14 to the preferred 1.3.5 on 2019-03-24, including 1.1.0 (2013-12-20), 1.1.1 (2014-03-25), 1.1.2 (2014-10-14), 1.2.0 (2015-05-19), 1.2.1 (2016-01-26), 1.2.2 (2016-06-22), 1.3.0 (2016-07-20), 1.3.1 (2016-11-25), 1.3.2 (2017-01-09), 1.3.3 (2018-07-18), and 1.3.4 (2019-03-01). Tags for each are available on its GitLab repository.

**Where can users learn more about Gappa?**  
The official website at http://gappa.gforge.inria.fr/ provides information in English. It appears under Open Hub ID gappa and Repology project name gappa-prover.

## Why It Matters
Gappa addresses the need for rigorous theorem proving in computational mathematics and formal verification by serving as an accessible proof assistant. Its status as free software under permissive licenses like CeCILL and GNU GPL v2.0 empowers researchers and developers worldwide to inspect, modify, and extend its capabilities without barriers, fostering collaborative advancements in automated reasoning. Backed by INRIA, a leading institution in computer science research, Gappa contributes to the ecosystem of open tools for ensuring mathematical correctness in software and algorithms, with its detailed version history reflecting sustained maintenance and evolution from 2013 to 2019.

## Notable For
- Dual licensing under CeCILL and GNU GPL v2.0, providing flexibility for both academic and commercial adaptations
- Development by INRIA, a premier French research institute in informatics and automation
- Extensive release cadence with 15 tagged versions from 1.0.0 in 2013 to preferred 1.3.5 in 2019
- GitLab-hosted repository with integrated issue tracking, supporting modern collaborative workflows
- Classification as both theorem prover and proof assistant, bridging automated and interactive verification
- English-language website hosted on GForge, alongside Open Hub and Repology integrations for discoverability
- Copyrighted free software model, balancing protection with open distribution (120 sitelinks)

## Body

### Core Classification and Description
Gappa operates as a theorem prover according to its Wikidata description. It qualifies as an instance of proof assistant. Additionally, it embodies free software, defined as software distributed under terms that allow users to freely run, study, change, and distribute it and modified versions, with a sitelink count of 120.

### Development and Organization
The Institut National de Recherche en Informatique et en Automatique serves as the developer. Gappa holds a copyrighted status despite its free software nature. Its Open Hub ID is gappa, and Repology lists it under the project name gappa-prover.

### Licensing Details
Gappa ships under the CeCILL license, with terms in the COPYING file at https://gitlab.inria.fr/gappa/gappa/-/blob/master/COPYING. It also includes the GNU General Public License version 2.0, specified in COPYING.GPL at https://gitlab.inria.fr/gappa/gappa/-/blob/master/COPYING.GPL.

### Official Resources and Access
The website resides at http://gappa.gforge.inria.fr/, presented in English. Source code lives at https://gitlab.inria.fr/gappa/gappa, using GitLab and programmed in OCaml. Issues appear at https://gitlab.inria.fr/gappa/gappa/-/issues.

### Version History
Gappa maintains a sequence of releases documented via GitLab tags:
- 1.0.0 on 2013-07-14: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.0.0
- 1.1.0 on 2013-12-20: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.1.0
- 1.1.1 on 2014-03-25: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.1.1
- 1.1.2 on 2014-10-14: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.1.2
- 1.2.0 on 2015-05-19: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.2.0
- 1.2.1 on 2016-01-26: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.2.1
- 1.2.2 on 2016-06-22: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.2.2
- 1.3.0 on 2016-07-20: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.0
- 1.3.1 on 2016-11-25: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.1
- 1.3.2 on 2017-01-09: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.2
- 1.3.3 on 2018-07-18: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.3
- 1.3.4 on 2019-03-01: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.4
- Preferred 1.3.5 on 2019-03-24: https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.5

This progression shows incremental updates over six years, from initial 1.0.0 to the marked preferred release.

## References

1. [Source](https://gitlab.inria.fr/gappa/gappa/-/blob/master/COPYING)
2. [Source](https://gitlab.inria.fr/gappa/gappa/-/blob/master/COPYING.GPL)
3. [Source](https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.0.0)
4. [Source](https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.1.0)
5. [Source](https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.1.1)
6. [Source](https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.1.2)
7. [Source](https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.2.0)
8. [Source](https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.2.1)
9. [Source](https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.2.2)
10. [Source](https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.0)
11. [Source](https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.1)
12. [Source](https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.2)
13. [Source](https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.3)
14. [Source](https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.4)
15. [Source](https://gitlab.inria.fr/gappa/gappa/-/tags/gappa-1.3.5)