30 research outputs found
An Abel-Jacobi invariant for cobordant cycles
We discuss an Abel-Jacobi invariant for algebraic cobordism cycles whose
image in topological cobordism vanishes. The existence of this invariant
follows by abstract arguments from the construction of Hodge filtered
cohomology theories in joint work of Michael J. Hopkins and the author. In this
paper, we give a concrete description of the new Abel-Jacobi map and Hodge
filtered cohomology groups for projective smooth complex varieties.Comment: v2: 21 pages; revised section 4; final version to appear in Doc. Mat
Hodge filtered complex bordism
We construct Hodge filtered cohomology groups for complex manifolds that
combine the topological information of generalized cohomology theories with
geometric data of Hodge filtered holomorphic forms. This theory provides a
natural generalization of Deligne cohomology. For smooth complex algebraic
varieties, we show that the theory satisfies a projective bundle formula and
\A^1-homotopy invariance. Moreover, we obtain transfer maps along projective
morphisms.Comment: minor revision; final version accepted for publication by the Journal
of Topolog
On the cokernel of the Thom morphism for compact Lie groups
We give a complete description of the potential failure of the surjectivity
of the Thom morphism from complex cobordism to integral cohomology for compact
Lie groups via a detailed study of the Atiyah-Hirzebruch spectral sequence and
the action of the Steenrod algebra. We show how the failure of the surjectivity
of the topological Thom morphism can be used to find examples of non-trivial
elements in the kernel of the induced differential Thom morphism from
differential cobordism of Hopkins and Singer to differential cohomology. These
arguments are based on the particular algebraic structure and interplay of the
torsion and non-torsion parts of the cohomology and cobordism rings of a given
compact Lie group. We then use the geometry of special orthogonal groups to
construct concrete cobordism classes in the non-trivial part of the kernel of
the differential Thom morphism.Comment: 36 pages, comments welcom
Geometric pushforward in Hodge filtered complex cobordism and secondary invariants
We construct a functorial pushforward homomorphism in geometric Hodge
filtered complex cobordism along proper holomorphic maps between arbitrary
complex manifolds. This significantly improves previous results on such
transfer maps and is a much stronger result than the ones known for
differential cobordism of smooth manifolds. This enables us to define and
provide a concrete geometric description of Hodge filtered fundamental classes
for all proper holomorphic maps. Moreover, we give a geometric description of a
cobordism analog of the Abel-Jacobi invariant for nullbordant maps which is
mapped to the classical invariant under the Hodge filtered Thom morphism. For
the latter we provide a new construction in terms of geometric cycles.Comment: 39 pages, comments very welcom