OBJ3 is a program specification and proof system based on order sorted equational logic. It has been successfully used for research and teaching in software design and specification, rapid prototyping, theorem proving, user interface design, and hardware verification, among other things. It was the first language to implement parameterized programming and its module system influenced the designs of the Ada, C++, and ML module systems.
Higher Order Logic (HOL) is a programming environment in which theorems can be proved and proof tools implemented. Built-in decision procedures and theorem provers can automatically establish many simple theorems. An Oracle mechanism gives access to external programs such as SAT and BDD engines. HOL 4 is particularly suitable as a platform for implementing combinations of deduction, execution, and property checking.
ACL2 is a mathematical logic, programming language, and mechanical theorem prover based on the applicative subset of Common Lisp. It is an "industrial-strength" version of the NQTHM or Boyer/Moore theorem prover, and has been used for the formal verification of commercial microprocessors, the Java Virtual Machine, interesting algorithms, and so forth.
Daikon is an implementation of dynamic detection of likely invariants. An invariant is a property (such as "x=2*y+5" or "this.next.prev = this" or "myarray is sorted by <") that holds at a certain point or points in a program. Invariants are often seen in assert statements, documentation, and formal specifications. Invariants can be useful in program understanding and a host of other applications. Daikon runs a program, observes the values that the program computes, and then reports properties that were true over the observed executions. It can detect properties in Java, C, C++, Perl, and IOA programs, in spreadsheet files, and in other data sources.
CZT is a Java framework and a suite of tools built on that framework for editing, type checking, and animating formal specifications written in the Z specification language. In addition to the ISO standard, there is some support for Z extensions, such as Object-Z, Circus and TCOZ.