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Watchlist (also hint list) is a mechanism that allows related proofs to guide a proof search for a new conjecture. This mechanism has been used with the Otter and Prover9 theorem provers, both for interactive formalizations and for human-assisted proving of open conjectures in small theories. In this work we explore the use of watchlists in large theories coming from first-order translations of large ITP libraries, aiming at improving hammer-style automation by smarter internal guidance of the ATP systems. In particular, we (i) design watchlist-based clause evaluation heuristics inside the E ATP system, and (ii) develop new proof guiding algorithms that load many previous proofs inside the ATP and focus the proof search using a dynamically updated notion of proof matching. The methods are evaluated on a large set of problems coming from the Mizar library, showing significant improvement of E's standard portfolio of strategies, and also of the previous best set of strategies invented for Mizar by evolutionary methods.

Watchlist (also hint list) is a technique that allows lemmas from related proofs to guide a saturation-style proof search for a new conjecture. ProofWatch is a recent watchlist-style method that loads many previous proofs inside the ATP, maintains their completion ratios during the proof search and focuses the search by following the most completed proofs. In this work, we start to use the dynamically changing vector of proof completion ratios as additional information about the saturation-style proof state for statistical machine learning methods that evaluate the generated clauses. In particular, we add the proof completion vectors to ENIGMA (efficient learning-based inference guiding machine) and evaluate the new method on the MPTP Challenge benchmark, showing moderate improvement in E’s performance over ProofWatch and ENIGMA.

In this work we describe a new learning-based proof guidance -ENIGMAWatch -for saturation-style first-order theorem provers. ENIGMAWatch combines two guiding approaches for the given-clause selection implemented for the E ATP system: ProofWatch and ENIGMA. ProofWatch is motivated by the watchlist (hints) method and based on symbolic matching of multiple related proofs, while ENIGMA is based on statistical machine learning. The two methods are combined by using the evolving information about symbolic proof matching as an additional information that characterizes the saturation-style proof search for the statistical learning methods. The new system is experimentally evaluated on a large set of problems from the Mizar library. We show that the added proof-matching information is considered important by the statistical machine learners, and that it leads to improvements in E's performance over ProofWatch and ENIGMA.

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