Exploiting Unique Fixed Points -- Scrap Your Type Applications -- Programming with Effects in Coq -- Verifying a Semantic ??-Conversion Test for Martin-Löf Type Theory -- The Capacity-C Torch Problem -- Recounting the Rationals: Twice! -- Zippy Tabulations of Recursive Functions -- Unfolding Abstract Datatypes -- Circulations, Fuzzy Relations and Semirings -- Asynchronous Exceptions as an Effect -- The Böhm-Jacopini Theorem Is False, Propositionally -- The Expression Lemma -- Nested Datatypes with Generalized Mendler Iteration: Map Fusion and the Example of the Representation of Untyped Lambda Calculus with Explicit Flattening -- Probabilistic Choice in Refinement Algebra -- Algebra of Programming Using Dependent Types -- Safe Modification of Pointer Programs in Refinement Calculus -- A Hoare Logic for Call-by-Value Functional Programs -- Synthesis of Optimal Control Policies for Some Infinite-State Transition Systems -- Modal Semirings Revisited -- Asymptotic Improvement of Computations over Free Monads -- Symmetric and Synchronous Communication in Peer-to-Peer Networks.

This book constitutes the refereed proceedings of the 9th International Conference on Mathematics of Program Construction, MPC 2008, held in Marseille, France in July 2008. The 18 revised full papers presented together with 1 invited talk were carefully reviewed and selected from 41 submissions. Issues addressed range from algorithmics to support for program construction in programming languages and systems. Topics of special interest are type systems, program analysis and transformation, programming language semantics, program logics.