Section: New Results

Combining inference systems in the CDSAT framework

Participant : Stéphane Graham-Lengrand.

In 2016 we had designed a methodology  [49], based on inference systems, for combining theories in SMT-solving, that supersedes the existing approaches, namely that of Nelson-Oppen [78] and that of MCSAT [86], [66]. While soundness and completeness of our approach were proved in 2016, we further developed, in 2017, the meta-theory of this system, now called CDSAT for Conflict-Driven Satisfiability, in particular with

• a proof of termination for the CDSAT system, and the identification of sufficient conditions, on the theory modules to be combined, for the global termination of the system to hold;

• a learning mechanism, whereby the system discovers lemmas along the run, which can be used later to speed-up the rest of the run;

• an enrichment of the CDSAT system with proof-object generation, and the identification of proof-construction primitives that can be used to make the answers produced by CDSAT correct-by-construction.

The first result, together with the introduction of the CDSAT framework, was publishing this year in [19]. The last two results are described in a paper accepted for publication at CPP in 2018.