BDDs verified in a proof assistant ( Preliminary report )

This paper is a case study in mechanical verification of graph manipulating algorithms: We prove the correctness of a family of algorithms constructing Binary Decision Diagrams in a monadic style. It distinguishes itself from previous verification efforts in two respects: Firstly, building the BDD structure is guided by a primitive recursive descent which makes the proof of termination trivial. Secondly, the development is modular: it is parametrized by primitives manipulating high-level hash tables that can be realized by several implementations.