Title: Characteristic classes in general relativity on a modified Poincare curvature bundle,
Abstract: Characteristic classes in space-time manifolds are discussed for both even-
and odd-dimensional spacetimes. In particular, it is shown that the
Einstein--Hilbert action is equivalent to a second Chern-class on a modified
Poincare bundle in four dimensions. Consequently, the cosmological constant and
the trace of an energy-momentum tensor become divisible modulo R/Z.