### Noncommutative rings and characteristic classes of foliations, by Igor Nikolaev

The notion of a characteristic fibration is introduced. This fibration
consists of a base space M and a set of fibres which are dimension
groups associated to a noncommutative ring R. Every dimension group
of the fibration is isomorphic to the first Betti group of M with
a `positive cone' depending continuously on the fibre. The characteristic
fibrations are linked to the codimension 1 regular foliations on M.
In particular, we prove that the characteristic classes of such foliations
coincide with the Stiefel-Whitney class of M.

Igor Nikolaev <inikolae@fields.utoronto.ca>