Alloy Analyzer vs HOL4

Alloy Analyzer is a free model-checking tool for describing systems in the Alloy language and exploring the structures those descriptions permit. It searches for structures that satisfy constraints and for counterexamples to properties. Models can represent collections of structures that change over time, including security configurations and switching network topologies. The Analyzer presents results graphically, with appearance options that can be tailored to a domain. Alloy 6 adds mutable state, temporal logic, and temporal model checking; that checking requires NuSMV or nuXmv to be installed and available in PATH. The self-contained executable includes the Pardinus/Kodkod model finder, SAT solvers, the standard Alloy library, tutorial examples, and source code. The same JAR can be used as an API in other applications. Sterling adds a web-based visualizer with graph and table views, customizable and extendable with JavaScript. Alloy is self-hosted, supports Linux, macOS, Windows, and API use, and is maintained by volunteers.

HOL4 is a free, interactive proof assistant for higher-order logic, with a programming environment for proving theorems and building proof tools. It supports work that combines deduction, execution, and property checking. Built-in decision procedures and theorem provers can establish many simple theorems, and an oracle mechanism can connect to external programs such as SMT and BDD engines. HOL4 supports higher-order logic and Standard ML, and can produce proof artifacts and counterexamples. It is self-hosted and listed for Linux, macOS, and Windows. A Standard ML compiler is required, with Poly/ML recommended; Moscow ML and MLTon are also supported for building tool executables. Windows installation can use Cygwin or the Windows Linux subsystem with Poly/ML. Moscow ML is another option, but the Windows guide notes that it is slower, lacks some Poly/ML libraries, and cannot run concurrent Holmake builds. HOL includes Emacs modes for syntax display and session interaction, and the installation guide links to Vim plugin documentation. Online materials include a tutorial, quick reference, FAQ, manuals, and generated indexes.