Using failure to guide inductive proof

Lemma discovery and generalization are two of the ma jor hurdles in automating inductive proof. This paper addresses aspects of these related problems. We build upon rippling, a heuristic which plays a pivotal role in guiding inductive proof. Rippling provides a high-level explanation of how to control the search for a proof. We demonstrate how this high-level explanation can be exploited productively when a proof attempt fails. In particular we show how failure can be used to focus the search for lemmas and generalizations.