CRM, Université de Montréal, Montréal H3C 3J7, Canada - Fields Institute, 222 College Stree, Toronto, Canada M5T 3J1
Abstract:
We introduce a continuous dimension function on the Grothendieck group over the crossed product -algebra . The function has an elegant geometry: on every minimal flow it takes the value of the ``rotation number" of ; such a problem was posed in 1936 by A. Weil.