Toma 0.7

Teppei Saito
Japan Advanced Institute of Science and Technology, Japan

Architecture

Toma is an automatic equational theorem prover based on a DISCOUNT loop [DKS97] implementing ordered completion [BDP89]. In addition to LPO and KBO, the tool also implements non-standard term orders such as weighted path orders [YKS15] and monotonic semantic path orders [BFR00].

Strategies

For this competition, the tool tries two runs for a given problem: one with a fixed KBO and another with an LPO. Based on an idea from [WM18], the precedence of the LPO is chosen in a way that minimizes the number of critical pairs between axioms, using the SMT solver Z3.

Implementation

For efficiency, Toma implements fingerprint indexing [Sch12], Waidmeister's AC heuristics [AHL03], and a connectedness testing [BD88, Sma21]. The source code is available at https://www.jaist.ac.jp/project/maxcomp/.

Expected Competition Performance

Toma would solve almost half as many problems as state-of-the-art solvers.