Institute for Logic, Language and Computation.
The Institute for Logic, Language and Computation (ILLC) is a research institute of the University of Amsterdam. ILLC's central research area is the study of fundamental principles of encoding, transmission and comprehension of information. Research at ILLC is interdisciplinary, and aims at bringing together insights from various disciplines concerned with information and information processing, such as logic, mathematics, computer science, linguistics, cognitive science, artificial intelligence and philosophy.
https://www.illc.uva.nl/
Computer Science Laboratory
Science, Math, Logic and Foundations, Institutions - SRI International. Computer Science Laboratory: Formal Methods and Dependable Systems.
http://csl.sri.com/
SYLLOGISM: Online program for Aristotelian Logic
SYLLOGISM: This site allows online experimentation with Aristotelian term logic, especially syllogistic reasoning. All the rules of Aristotelian logic have been implemented.Thus automatic proofs are possible. There is also a construction of semantic models of Aristotelian logic.
http://aristotelianlogic.glashoff.net
Mizar Home Page
Science, Math, Logic and Foundations, Foundations - Mizar Project. An attempt to reconstruct mathematical vernacular into a formal language which can be read by humans and also verified by software.
https://www.mizar.org/
The Coq proof assistant
Science, Math, Logic and Foundations, Computational Logic - The Coq proof assistant. Allows the user to handle calculus assertions, to check mechanically proofs of these assertions, helps to find formal proofs, extracts a certified program from the constructive proof of its formal specification.
https://coq.inria.fr/
The HOL Theorem Proving System
Science, Math, Logic and Foundations, Computational Logic - The HOL Theorem Proving System. The system documented originated at the Laboratory for Applied Logic of Brigham Young University and features higher-order, classical, natural deduction with tactics.
https://hol.sourceforge.net/
Isabelle
Science, Math, Logic and Foundations, Computational Logic - Isabelle. Homepage of the theorem prover environment developed by Larry Paulson at Cambridge University and Tobias Kipkow at TU Munich.
http://isabelle.informatik.tu-muenchen.de/