OpenJML vs PVS

OpenJML has no write-up on Specifiction yet; its figures are above.

PVS is a mechanized environment for formal specification and verification, intended for work such as mathematical formalization and hardware or algorithm verification. Its language is based on typed higher-order logic and supports predicate subtypes, dependent types, and parameterized theories. The system combines predefined theories, a type checker, interactive theorem prover, symbolic model checker, utilities, libraries, documentation, and examples. Proof support includes induction, rewriting, simplification with decision procedures, abstraction, and symbolic model checking; command-line tools can re-prove theories and libraries in batch mode. PVS also integrates the Yices SMT solver, supports random testing during proofs, and includes PVSio for evaluation and animation. GNU or X Emacs provides the integrated interface, with Tcl/Tk displays for proof trees and theory hierarchies. It runs on Linux, macOS, and Windows and is self-hosted. Noncommercial use is listed at free. Sources are under GPL, but the Allegro runtime has a separate click-through license, and commercial users need a current PVS license or must contact SRI about licensing.