A generic theorem prover with support for
several object-logics, developed by Lawrence C. Paulson
<Larry.Paulson@cl.cam.ac.uk> in collaboration with
Tobias Nipkow at the Technical University of Munich.
A system of type classes allows
polymorphic object-logics
with
overloading and automatic
type inference.
Isabelle supports
first-order logic -
constructive and
classical versions; higher-order logic, similar to Gordon's
HOL; Zermelo Fr?nkel set theory; an
extensional version
of Martin L?f's type theory, the classical first-order
sequent calculus,
LK; the modal logics
T, S4, and
S43; and
Logic for Computable Functions.
An object logic's
syntax and inference rules are specified
declaratively allowing single-step proof construction.
Proof procedures can be expressed using "tactics" and
"tacticals". Isabelle provides control structures for
expressing search procedures and generic tools such as
simplifiers and classical theorem provers which can be applied
to object-logics. Isabelle is built on top of
Standard ML
and uses its user interface.
http://cl.cam.ac.uk/Research/HVG/Isabelle/.
Mailing list: isabelle-users@cl.cam.ac.uk.