What is Isabelle?
Isabelle is a generic proof assistant. It allows mathematical formulas to be expressed in a formal language and provides tools for proving those formulas in a logical calculus. Isabelle was originally developed at the University of Cambridge and Technische Universität München, but now includes numerous contributions from institutions and individuals worldwide. See the Isabelle overview for a brief introduction.
Now available: Isabelle2015
Download for Linux
Download for Windows
Download for Mac OS XSome highlights:
- Improved Isabelle/jEdit Prover IDE: folding / bracket matching for Isar, support for BibTeX files, improved graphview panel, improved scheduling for asynchronous print commands (e.g. Sledgehammer provers).
- Support for private and qualified name space modifiers.
- Structural composition of proof methods (meth1; meth2) in Isar.
- HOL: BNF datatypes and codatatypes are now standard.
- HOL: numerous tool improvements: Nitpick, Sledgehammer, SMT, including a new free (!) version of Z3.
- HOL: numerous library refinements and enhancements.
- New proof method "rewrite" for single-step rewriting with subterm selection based on patterns.
- New Eisbach proof method language and "match" method.
- Updated manuals: datatypes, implementation, isar-ref, jedit, sledgehammer, system.
See also the cumulative NEWS.
Distribution & Support
Isabelle is distributed for free under a conglomerate of open-source licenses, but the main code-base is subject to BSD-style regulations. The application bundles include source and binary packages and documentation, see the detailed installation instructions. A vast collection of Isabelle examples and applications is available from the Archive of Formal Proofs.
Support is available by ample documentation, the Isabelle community Wiki, Stack Overflow, and in particular the following mailing lists:
- isabelle-users@cl.cam.ac.uk provides a forum for Isabelle users to discuss problems, exchange information, and make announcements. Users of official Isabelle releases should subscribe or see the archive (also available via Google groups and Narkive).
- isabelle-dev@in.tum.de covers the Isabelle development process, including intermediate repository versions, and administrative issues concerning the website or testing infrastructure. Early adopters of repository versions should subscribe or see the archive (also available at mail-archive.com or gmane.org).