Ugo de Liguoro, Adolfo Piperno. Must Preorder in Non-Deterministic Untyped Lambda-Calculus. In Jean-Claude Raoult, editor, CAAP 92, 17th Colloquium on Trees in Algebra and Programming, Rennes, France, February 26-28, 1992, Proceedings. Volume 581 of Lecture Notes in Computer Science, pages 203-220, Springer, 1992.
Abstract is missing.