Better Automation for TLA+ Proofs

Article court pour les 31e Journées Francophones des Langages Applicatifs (JFLA 2020)International audienceTLA+ is a specification language based on traditional untyped set theory. It is equipped with a set of tools, including the TLA+ proof system TLAPS, which uses trusted back-end solvers to handle individual proof steps-referred to as "proof obligations". As most solvers rely on and benefit from typed formalisms, types are first reconstructed for the obligations; however, the current encoding into the SMT-LIB format does not exploit all of this type information. In this paper, we present motivations for a more pervasive usage of types at an intermediate representation of TLA+ proof obligations, and describe work in progress on several improvements of TLAPS: a type-driven SMT encoding, a tactic for instantiation hints, and type annotations for the language. We conclude with some perspectives for future work

Tactiques de preuve dans Dedukti

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Improving Automation for Higher-Order Proof Steps

International audienceWe have extended the TLA+ proof system TLAPS with a new backend to improve the automation of proof steps that involve higher-order reasoning. The current support for such steps is poor, requiring the user to break down proofs into unnecessarily small steps. We defined a translation from TLA+ to THF, the TPTP dialect for higher-order logic, and evaluated several higher-order solvers on proof obligations generated from the standard library of TLA+. Our results demonstrate that the solvers are able to handle much coarser proof steps than the other strategies provided by TLAPS, reducing the amount of necessary user interactions by a significant margin

Better Automation for TLA+ Proofs

Article court pour les 31e Journées Francophones des Langages Applicatifs (JFLA 2020)International audienceTLA+ is a specification language based on traditional untyped set theory. It is equipped with a set of tools, including the TLA+ proof system TLAPS, which uses trusted back-end solvers to handle individual proof steps—referred to as “proof obligations”. As most solvers rely on and benefit from typed formalisms, types are first reconstructed for the obligations; however, the current encoding into the SMT-LIB format does not exploit all of this type information. In this paper, we present motivations for a more pervasive usage of types at an intermediate representation of TLA+ proof obligations, and describe work in progress on several improvements of TLAPS: a type-driven SMT encoding, a tactic for instantiation hints, and type annotations for the language. We conclude with some perspectives for future work

Higher-order Automation in TLAPS

Résumé de présentation pour le "Community Event" TLA+ de 2020International audienc