On the Dynamic Increase of Multiplicities in Matrix Proof Methods for Classical Higher-Order Logic

Abstract

A major source of the undecidability of a logic is the number of instances—the so-called multiplicities—of existentially quantified formulas that are required in a proof. We consider the problem in the context of matrix proof methods for classical higher-order logic and present a technique which improves the standard practice of iterative deepening over the multiplicities. We present a mechanism that allows to adjust multiplicities on demand during matrix-based proof search and not only preserves existing substitutions and connections, but additionally adapts them to the parts that result from the increase of the multiplicities.