Hierarchical invention of theorem proving strategies

State-of-the-art automated theorem provers (ATPs) such as E and Vampire use a large number of different strategies to traverse the search space. Inventing targeted proof search strategies for specific problem sets is a difficult task. Several machine learning methods that invent strategies automatically for ATPs have been proposed previously. One of them is the Blind Strategymaker (BliStr) system for inventing strategies of the E prover. In this paper we describe BliStrTune - a hierarchical extension of BliStr. BliStrTune explores much larger space of E strategies than BliStr by interleaving search for high-level parameters with their fine-tuning. We use BliStrTune to invent new strategies based also on new clause weight functions targeted at problems from large ITP libraries. We show that the new strategies significantly improve E's performance.