Section: Software and Platforms

Bedwyr

Participants : Quentin Heath, Dale Miller [correspondant] .

Main web-site: http://slimmer.gforge.inria.fr/bedwyr/ .

During the first half of 2013, Quentin Heath was working as an engineer on the team, supported by the BATT ADJ project funded by Inria. During that time, we worked exclusively on making improvements to Bedwyr. In particular, he made extensive and important changes to the tabling mechanism of Bedwyr, a feature of model checking systems that is capable of remembering past successful proofs (it can even support a finite failure as a successful proof of a negation). These extension allow lemmas to be used to greatly extend the scope of what can be inferred from a table. For example, if we are attempting to show that there is a winning strategy for a given board position, we would certainly like to make use of a lemma that allows one to infer that winning strategies are preserved under symmetries of the board. There are a number of design issues that go along with the design of such a tabling mechanism: for example, should one use such lemmas in a forward-chaining or backward-chaining fashion. Quentin has tested both of these options in order to collect information as to what the trade-offs would be.

We should note that Quentin Heath is now a PhD student on the team and is addressing a number of theoretical questions related to his research on Bedwyr.