Memoization-Based Proof Search in LF - an Experimental Evaluation of a Prototype

Elf is a general meta-language for the specification and implementation of logical systems in the style of the logical framework LF. Proof search in this framework is based on the operational semantics of logic programming. In this paper, we discuss experiments with a prototype for memoization-based proof search for Elf programs. We compare the performance of memoization-based proof search, depth-first search and iterative deepening search using two applications: 1) Bi-directional type-checker with subtyping and intersection types 2) Parsing of formulas into higher-order abstract syntax. These experiments indicate that memoization-based proof search is a practical and overall more efficient alternative to depth-first and iterative deepening search.