Breadth-first traversal following a proposal of Martin Hofmann (suggested with different degrees of detail between 1993 and 1995)
Authors: Ulrich Berger, Ralph Matthes, Anton Setzer
This is code supplementing the paper "Martin Hofmann’s case for non-strictly positive data types" by Berger, Matthes and Setzer, in the LIPIcs post-proceedings of TYPES 2018 (LIPIcs vol. 130): DOI: 10.4230/LIPIcs.TYPES.2018.1.