| 概要 | A noncompact smooth manifold X has a real algebraic structure if
and only if X is tame at infinity, i.e. X is the interior of a
compact manifold with boundary.Different algebraic structures on
X can be detected by the topology of an algebraic compactification
with normal crossings at infinity. The resulting filtration of the
homology of X is analogous to Deligne's weight filtration for
nonsingular complex algebraic varieties. |