j'Imp Theorem Prover
- An automatic theorem prover based on set of support and ordered resolution for first-order logic. j'Imp is part of the Orbital library. This library is a Java class providing object-oriented representations and algorithms for logic, mathematics, and arti
- http://www.functologic.com/logic/jImp.html

Bertrand
- Bertrand solves sets of first-order predicate logic statements for satisfiability (consistency), validity, and equivalence. It also checks single statements for "logical truth" (tautology) and "logical falsity" (self-contradiction).
- http://www.uwosh.edu/faculty_staff/herzberg/Bertrand.html

CrocoPat: Simple and Efficient Relational Programming
- CrocoPat manipulates relations of any arity, including graphs (which are binary relations). Its simple and expressive query and manipulation language is based on first-order predicate calculus. The implementation is based on the data structure binary deci
- http://mtc.epfl.ch/~beyer/CrocoPat/

ModLeanTAP: Lean Tableau-based Deduction for Propositional Modal Logics
- Lean Tableau-based Deduction for Propositional Modal Logics. By Bernhard Beckert.
- http://i12www.ira.uka.de/modlean/

WinKE
- An interactive proof assistant based on analytic tableaux, and designed for the teaching of deductive reasoning. Ordering information is available at this site, as are academic papers on the design of the software.
- http://staff.science.uva.nl/~ulle/WinKE/

Church
- Program understands the different types of lambda expressions, can extract lists of variables (both free and bound) and subterms, and can simplify complicated expressions. Uses Python.
- http://www.alcyone.com/software/church/

Proof General
- Comprehensive Gnu-Emacs and XEmacs interface for several theorem provers including Coq, Isabelle, Lego, and Phox.
- http://proofgeneral.inf.ed.ac.uk

VeriFun
- A semi-automated system for the verification of statements about programs written in a functional programming language. The system is capable of following fully-automated routines for theorem proving and hypotheses formation, as well as operating interact
- http://www.informatik.tu-darmstadt.de/pm/verifun/

DC Proof Online
- New proof-writing software to teach the fundamentals of logic and proof. Enables users/students to write error-free proofs by selecting rules of inference, axioms, etc. from convenient drop-down menus. Includes tutorial and exercises.
- http://www.dcproof.com

DELORES
- A forward-chaining reasoning engine for defeasible logic, a less expressive but more efficient nonmonotonic logic.
- http://www.dfki.uni-kl.de/~miller/delores/

Paradox
- A tool that processes first-order logic problems and tries to find finite-domain models for them; written by Koen Claessen and Niklas Sörensson. Haskell and C++; free download under GPL.
- http://www.cs.chalmers.se/~koen/paradox/

llprover
- A linear logic prover that searches a cut-free proof for the given two-sided sequent of first-order linear logic.
- http://bach.scitec.kobe-u.ac.jp/llprover/

Gateway to Logic
- A collection of web-based logic programs offering a number of logical functions: interactively or automatically build proofs, check theorems, and operate on propositional logic formulae.
- http://logik.phl.univie.ac.at/~chris/formular-uk.html

ACL2 Version 2.7
- A programming language in which you can model computer systems and a tool to help prove properties of those models. Available under GPL and runs on various platforms. Includes related download links.
- http://www.cs.utexas.edu/users/moore/acl2/

Tree Proof Generator
- An implementation of the semantic tableaux method for classical propositional and predicate logic, written in JavaScript/DOM.
- http://www.umsu.de/logik/trees

Visual Turing
- A graphical IDE for creating, running and debugging Turing machines. Freeware for Windows 95/98/NT/2000.
- http://www.cheransoft.com/vturing/

PVS
- The PVS Specification and Verification System. Available for Sparc machines with Solaris 2 and Intel x86 Machines with Linux compatible with Redhat 5 or later. Required is Emacs (version 19 or later), recommended LaTeX and Tcl/Tk. Download by FTP.
- http://pvs.csl.sri.com/

LOOM
- A language and environment for constructing intelligent applications. It is a research project in the Artificial Intelligence research group at the University of Southern California's Information Sciences Institute. The goal of the project is to develop
- http://www.isi.edu/isd/LOOM/LOOM-HOME.html

ProofPower
- A suite of tools supporting specification and proof in Higher Order Logic (HOL) and in Z notation.
- http://www.lemma-one.com/ProofPower/index/

Logic Software from CSLI
- By Jon Barwise and John Etchemendy.
- http://www-csli.stanford.edu/hp/Logic-software.html

The Coq Project
- Deals with effectively machine-checked formal mathematics. In practice, this includes the study of mathematical formalisms well-suited for implementations, the implementations themselves and the use of these for various applications. Focuses on software c
- http://pauillac.inria.fr/coq/

Isabelle
- A generic theorem proving environment developed at Cambridge University (Larry Paulson) and TU Munich (Tobias Nipkow). Includes logic, documentation and free download.
- http://www.cl.cam.ac.uk/Research/HVG/Isabelle/

MUltlog
- Takes as input the specification of a finitely-valued first-order logic and produces a sequent calculus, a natural deduction system, and clause formation rules for this logic.
- http://www.logic.at/multlog/

MUltseq
- A generic sequent prover for propositional finitely-valued logics.
- http://www.logic.at/multseq/

Automated Reasoning Project
- Web resource provided by research group. Includes access to software developed by the team, coverering such projects as FINDER (Finite Domain Enumerator), MaGIC (Matrix Generator for Implication Connectives) and Kripke (A theorem prover for the relevant
- http://cslab.anu.edu.au/ar/

Database of Existing Mechanized Reasoning Systems
- A list (>50 entries) of automatic resolution provers (like Otter), interactive provers (like PVS) and other mechanized reasoning tools.
- http://www-formal.stanford.edu/clt/ARS/systems.html

PROTEIN
- A PROver with a Theory Extension INterface. Theorem prover for first-order clause logic, written in ECRC's Prolog-dialect ECLiPSe. Free download, documentation.
- http://www.uni-koblenz.de/ag-ki/Implementierungen/Protein/

LWB
- Logics Workbench.
- http://www.lwb.unibe.ch/