D45 Prover Enhancement

Overview

• Two tasks concerned the prover performance from the core platform: the addition of rewriting and inference rules, and the addition of a mechanism to allow the customization and the parametrization or combination of tactics. While the addition of rewriting and inference rules has always been a regular task to enhance the Rodin integrated prover during DEPLOY lifetime, a new way to manage tactics has been implemented. In fact, the user is now able to define various types of tactics called 'profiles' which could be customized and parameterized tactics to discharge some specific proof obligations.
• TODO An overview of the contribution about the ProB Disprover (Daniel Plagge, Jens Bendiposto)
• The SMT Solvers plug-in allowing to use the SMT solvers within Rodin is an effective alternative to the Atelier-B provers, particularly when reasoning on linear arithmetic. TODO (Laurent Voisin, Yoann Guyot)

Motivations

New rewriting and inference rules

In an Event-B development, more than 60% of the time is spent on proofs. It has been a continuous aim to increase the number of automatically discharged proof obligations (POs) by improving the capabilities of the integrated sequent prover through the addition of rewriting and inference rules. These rules were provided through tactics, or existing or newly created. These tactics were automatic, or manual, or sometimes both. Providing new proving rules, even if it sometimes does not increase directly the number of automatically discharged POs aims to help the user to interactively discharge them and spare his time.

Advanced Preferences for Auto-tactics

Sometimes, the automatic prover fails because the order of the applied tactics doesn't lead to discharge the proof obligation. Previously the ordering of tactics was lost at each change. Another issue is to have more than one possibility to combine the tactics. Indeed, various combinators called tacticals allow to combine tactics in a specific manner, thus providing a sort of tactic arithmetic. The advanced preferences for auto-tactics solved these two issues.

Isabelle Plug-in

TODO To be completed by Matthias Schmaltz

ProB Disprover

TODO Daniel Plagge, Jens Bendiposto

SMT Solver Integration

TODO Laurent Voisin & Yoann Guyot

Choices / Decisions

New rewriting and inference rules

TODO To be completed by Laurent Voisin

Advanced Preferences for Auto-tactics

TODO To be completed by Nicolas Beauger Since Rodin 2.1, simple tactic profiles have been added. They allow to persiste and set specifically for some project various ordered ways to apply the basic tactics. Since Rodin 2.3, tacticals and parameterisation have been added to the profiles increasing even more the potential of such proving feature. The combinators allow for exemple to loop on a subset of tactics, including existing profiles, and the parameterisation allows for example to set a timeout on external provers such as AtelierB P1.

Isabelle Plug-in

TODO To be completed by Matthias Schmaltz

ProB Disprover

TODO Daniel Plagge, Jens Bendiposto

SMT Solver Integration

TODO Laurent Voisin & Yoann Guyot

Available Documentation

• TODO Links for New rewriting and inference rules
• TODO Links for Advanced Preferences for Auto-tactics
• TODO Links for Isabelle Plug-in
• TODO Links for ProB Disprover
• TODO Links for SMT Solver Integration

Status

New rewriting and inference rules

TODO To be completed by Laurent Voisin

Advanced Preferences for Auto-tactics

TODO To be completed by Nicolas Beauger

Isabelle Plug-in

TODO To be completed by Matthias Schmaltz

ProB Disprover

TODO Daniel Plagge, Jens Bendiposto

SMT Solver Integration

TODO Laurent Voisin & Yoann Guyot