Everything You Always Wanted to Know About Generalization of Proof Obligations in PDR

In this article, we revisit the topic of generalizing proof obligations (POs) in bit-level property directed reachability (PDR). We provide a comprehensive study which: 1) determines the complexity of the problem; 2) thoroughly analyzes limitations of existing methods; 3) introduces approaches to PO generalization that have never been used in the context of PDR; 4) compares the strengths of different methods from a theoretical point of view; and 5) intensively evaluates the methods on various benchmarks from the hardware model checking as well as from AI planning.