A New Index for Polytopes.
A note on product structures on Hochschild homology of schemes
We extend the definition of Hochschild and cyclic homologies of a scheme over a commutative ring k to define the Hochschild homologies HH⁎(X/S) and cyclic homologies HC⁎(X/S) of a scheme X with respect to an arbitrary base scheme S. Our main purpose is to study product structures on the Hochschild homology groups HH⁎(X/S). In particular, we show that carries the structure of a graded algebra.
A Note on the First Rigid Cohomology Group for Geometrically Unibranch Varieties
A support theorem for Hilbert schemes of planar curves
Consider a family of integral complex locally planar curves whose relative Hilbert scheme of points is smooth. The decomposition theorem of Beilinson, Bernstein, and Deligne asserts that the pushforward of the constant sheaf on the relative Hilbert scheme splits as a direct sum of shifted semisimple perverse sheaves. We will show that no summand is supported in positive codimension. It follows that the perverse filtration on the cohomology of the compactified Jacobian of an integral plane curve...
Algebraic cobordism of bundles on varieties
The double point relation defines a natural theory of algebraic cobordism for bundles on varieties. We construct a simple basis (over ) of the corresponding cobordism groups over Spec() for all dimensions of varieties and ranks of bundles. The basis consists of split bundles over products of projective spaces. Moreover, we prove the full theory for bundles on varieties is an extension of scalars of standard algebraic cobordism.
Algebraic cycles in families of abelian varieties over Hilbert-Blumenthal surfaces.
Algebraic equivalence of real algebraic cycles
Given a compact nonsingular real algebraic variety we study the algebraic cohomology classes given by algebraic cycles algebraically equivalent to zero.
Algebraically constructible chains
We construct for a real algebraic variety (or more generally for a scheme essentially of finite type over a field of characteristic ) complexes of algebraically and - algebraically constructible chains. We study their functoriality and compute their homologies for affine and projective spaces. Then we show that the lagrangian algebraically constructible cycles of the cotangent bundle are exactly the characteristic cycles of the algebraically constructible functions.
Asymptotic purity for very general hypersurfaces of ℙn × ℙn of bidegree (k, k)
For a complex irreducible projective variety, the volume function and the higher asymptotic cohomological functions have proven to be useful in understanding the positivity of divisors as well as other geometric properties of the variety. In this paper, we study the vanishing properties of these functions on hypersurfaces of ℙn × ℙn. In particular, we show that very general hypersurfaces of bidegree (k, k) obey a very strong vanishing property, which we define as asymptotic purity: at most one asymptotic...