Limited resource strategy in resolution theorem proving

Abstract

For most applications of first-order theorem provers a proof should be found within a fixed time limit. When the time limit is set, systems can perform much better by using algorithms other than the ordinary complete ones. In this paper we describe the limited resource strategy (LRS) intended to improve performance of the OTTER saturation algorithm when a fixed limit is imposed on the time of a run. The strategy is adaptive in the following sense: it adjusts the limit on the weight of clauses according to some statistics collected on the earlier stages of proof search. We give experimental evidence that the LRS gives a considerable improvement over the OTTER saturation algorithm. We also show that it is superior to the DISCOUNT algorithm, which does not use passive clauses for simplification, and to the non-adaptive weight-based algorithms.