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: (February 2021)
Hardware requirements:
- Small experiments: 4 GB memory, 2 CPU cores
- Medium applications: 8 GB memory, 4 CPU cores
- Large projects: 16 GB memory, 8 CPU cores
- Extra-large projects: 64 GB memory, 16 CPU cores
Some notable changes:
- Improved HTML presentation in Isabelle/Scala, using PIDE markup.
- Improved PDF document preparation in Isabelle/Scala, using LuaLaTeX.
- Isabelle/jEdit: improved monitoring of Java and ML process. -
- Isabelle/jEdit: look-and-feel and IDE feedback improvements. +
- Isabelle/jEdit: improved look-and-feel and IDE feedback.
- Pure: improved handling of named contexts and local syntax bundles.
- HOL: substantially reworked support for Word library.
- HOL: various syntax and library improvements.
- HOL: various Sledgehammer and SMT improvements, with updated external tools.
- HOL: support for Nitpick/Kodkod in Isabelle/Scala.
- ML: routine support for Isabelle/Scala functions in Isabelle/ML.
- System: support for Isabelle/Scala services defined in user-space. -
- Experimental support for ARM64 platform on Linux and macOS (Apple Silicon). +
- Partial support for ARM64 platform on Linux and macOS (Apple Silicon).
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 the official documentation and 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.
- 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 development snapshots or repository versions should subscribe or see the archive (also available at mail-archive.com).
Zulip Chat is a real-time discussion platform to exchange ideas, ask questions, and collaborate on Isabelle projects, with minimalistic public archive.
Stack Overflow is a question-and-answer platform, with complex review process but limited discussion facilities.