Residual Theory in Lambda-Calculus. We present the complete development in Gallina of the residual theory of beta-reduction in pure lambda-calculus. The main result is the Prism Theorem, and its corollary Lévy's Cube Lemma, a strong form of the parallel-moves lemma, itself a key step towards the confluence theorem and its usual corollaries (Church-Rosser, uniqueness of normal forms).
opam install coq-lambda.8.8.0