An Induction Principle for Pure Type Systems

Abstract

We present an induction principle for Pure Type Systems and use that principle to define CPS translations and to solve partially the -- open -- problem of Expansion Postponement. Our principle strengthens and generalises similar principles by Dowek, Huet and Werner [12] and Barthe, Hatcliff and Sørensen [5], which have been respectively used to define eta-long normal forms and CPS translations for the systems of Barendregt's lambda-cube [2, 3]