The dollar and policy options

Dollar, American ; Foreign exchange - Law and legislation

A note on the Penon definition of nn-category

We show that doubly degenerate Penon tricategories give symmetric rather than braided monoidal categories. We prove that Penon tricategories cannot give all tricategories, but we show that a slightly modified version of the definition rectifies the situation. We give the modified definition, using non-reflexive rather than reflexive globular sets, and show that the problem with doubly degenerate tricategories does not arise.Comment: 14 pages, to appear in Cahiers de Topologie et Geometrie Differentielle Categorique