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Admin/page/index.html

author | wenzelm |

Wed, 07 Apr 1999 15:43:16 +0200 | |

changeset 6411 | 07e95e4cfefe |

parent 6150 | 71974ec3ebfb |

child 7948 | 61102e8cbe3c |

permissions | -rw-r--r-- |

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<html> <head> <!-- $Id$ --> <title>Isabelle</title> </head> <body> <h1>Isabelle </h1> <a href="http://isabelle.in.tum.de/logo/"><img src="isabelle.gif" width=100 align=right alt="[Isabelle logo]"></a> <p> <strong>Isabelle</strong> is a popular generic theorem proving environment developed at Cambridge University (<a href="http://www.cl.cam.ac.uk/users/lcp/">Larry Paulson</a>) and TU Munich (<a href="http://www.in.tum.de/~nipkow/">Tobias Nipkow</a>). <p> <a href="http://www.cl.cam.ac.uk/Research/HVG/Isabelle/cambridge.html"><img src="cambridge.gif" width=145 border=0 align=right alt="[Cambridge logo]"></a> <a href="http://isabelle.in.tum.de/munich.html"><img src="munich.gif" width=48 border=0 align=right alt="[Munich logo]"></a> This page provides general information on Isabelle, more specific information is available from the local pages <ul> <li> <a href="http://www.cl.cam.ac.uk/Research/HVG/Isabelle/cambridge.html"><strong>Isabelle at Cambridge</strong></a> <li> <a href="http://isabelle.in.tum.de/munich.html"><strong>Isabelle at Munich</strong></a> </ul> See there for information on projects done with Isabelle, mailing list archives, research papers, the Isabelle bibliography, and Isabelle workshops and courses. <h2>Obtaining Isabelle</h2> The latest version is <strong>Isabelle98-1</strong>, it is available from several <a href="dist/">mirror sites</a>. <h2>What is Isabelle?</h2> Isabelle can be viewed from two main perspectives. On the one hand it may serve as a generic framework for rapid prototyping of deductive systems. On the other hand, major existing logics like <strong>Isabelle/HOL</strong> provide a theorem proving environment ready to use for sizable applications. <h3>Isabelle's Logics</h3> The Isabelle distribution includes a large body of object logics and other examples (see the <a href="library/">Isabelle theory library</a>). <dl> <dt><a href="library/HOL/"><strong>Isabelle/HOL</strong></a><dd> is a version of classical higher-order logic resembling that of the <A HREF="http://www.cl.cam.ac.uk/Research/HVG/HOL/HOL.html">HOL System</A>. <dt><a href="library/HOLCF/"><strong>Isabelle/HOLCF</strong></a><dd> adds Scott's Logic for Computable Functions (domain theory) to HOL. <dt><a href="library/FOL/"><strong>Isabelle/FOL</strong></a><dd> provides basic classical and intuitionistic first-order logic. It is polymorphic. <dt><a href="library/ZF/"><strong>Isabelle/ZF</strong></a><dd> offers a formulation of Zermelo-Fraenkel set theory on top of FOL. </dl> <p> Isabelle/HOL is currently the best developed object logic, including an extensive library of (concrete) mathematics, and various packages for advanced definitional concepts (like (co-)inductive sets and types, well-founded recursion etc.). The distribution also includes some large applications, for example correctness proofs of cryptographic protocols (<a href="library/HOL/Auth/">HOL/Auth</a>) or communication protocols (<a href="library/HOLCF/IOA/">HOLCF/IOA</a>). <p> Isabelle/ZF provides another starting point for applications, with a slightly less developed library. Its definitional packages are similar to those of Isabelle/HOL. Untyped ZF provides more advanced constructions for sets than simply-typed HOL. <p> There are a few minor object logics that may serve as further examples: <a href="library/CTT/">CTT</a> is an extensional version of Martin-Löf's Type Theory, <a href="library/Cube/">Cube</a> is Barendregt's Lambda Cube. There are also some sequent calculus examples under <a href="library/Sequents/">Sequents</a>, including modal and linear logics. Again see the <a href="library/">Isabelle theory library</a> for other examples. <h3>Defining Logics</h3> Logics are not hard-wired into Isabelle, but formulated within Isabelle's meta logic: <strong>Isabelle/Pure</strong>. There are quite a lot of syntactic and deductive tools available in generic Isabelle. Thus defining new logics or extending existing ones basically works as follows: <ol> <li> declare concrete syntax (via mixfix grammar and syntax macros), <li> declare abstract syntax (as higher-order constants), <li> declare inference rules (as meta-logical propositions), <li> instantiate generic automatic proof tools (simplifier, classical tableau prover etc.), <li> manually code special proof procedures (via tacticals or hand-written ML). </ol> The first three steps above are fully declarative and involve no ML programming at all. Thus one already gets a decent deductive environment based on primitive inferences (by employing the built-in mechanisms of Isabelle/Pure, in particular higher-order unification and resolution). For sizable applications some degree of automated reasoning is essential. Instantiating existing tools like the classical tableau prover involves only minimal ML-based setup. One may also write arbitrary proof procedures or even theory extension packages in ML, without breaching system soundness (Isabelle follows the well-known <em>LCF system approach</em> to achieve a secure system). <h2>Mailing list</h2> Use the mailing list <a href="mailto: isabelle-users@cl.cam.ac.uk">isabelle-users@cl.cam.ac.uk</a> to discuss problems and results. (Why not <A HREF="mailto:lcp@cl.cam.ac.uk">subscribe</A>?) </body> </html>