Previous Special Year Seminar

Apr
19
2007

Motivic Cohomology

Completion of the Proof of the Bloch-Kato Conjecture
Chuck Weibel
11:00am|S-101

In the last eight lectures, we have reduced the proof of the Bloch-Kato to an assertion about motivic cohomology operations. We will prove that this assertion is correct, and so complete the proof of the Bloch-Kato conjecture.

Apr
12
2007

Motivic Cohomology

Overconvergent Homotopy Invariant Presheaves with Transfers over Smooth Rigid Varieties
11:00am|S-101

Let F be a presheaf with transfers on the category of smooth affinoid varieties over a non-archemidean field. Suppose that F is overconvergent and homotopy invariant. Then the presheaves H^i(-,F) are also homotopy invariant (where the cohomology is...

Apr
10
2007

Complex Algebraic Geometry

Wonderful Compactification of an Arrangement of Subvarieties
Li Li
2:00pm|S-101

Consider an arrangement of nonsingular subvarieties in a nonsingular algebraic variety. We define a compactification of the complement by replacing these subvarieties with a normal crossing divisor. This compactification is obtained by a sequence of...

Mar
15
2007

Motivic Cohomology

Cycles on Complete Intersections
12:00pm|S-101

We will describe some bounds on the multidegrees of complete intersections to have trivial Chow groups in low dimensions.

Mar
14
2007

Complex Algebraic Geometry

On the Abel-Radon Transform of Locally Residual Currents with Respect to a Family of Complete Intersections
2:30pm|S-101

Let $X\subset \P^N$ be a projective submanifold of dimension $n$ in the complex projective space $\P^N$. Let $U$ be a domain in the parameter space $T$ of complete intersections of codimension $m$ and of a given bidegree $(d_1,\dots,d_m)$ in $\P^N$...

Mar
08
2007

Motivic Cohomology

Operations with Integer Coefficients (After Voevodsky)
11:00am|S-101

We will classify all unstable motivic operations from bidegree (2n,n) (with coefficients Z) to bidegree (p,q) with coefficients Z/l, l>2. All such operations are polynomials on the elements of the Steenrod Algebra. This work is based upon some...

Mar
07
2007

Complex Algebraic Geometry

Canonical Frames for Nonholonomic Vector Distributions
Igor Zelenko
1:00pm|S-101

The talk is based on the joint work with Boris Doubrov. First we will describe a new rather effective procedure of symplectification for the problem of local equivalence of nonholonomic vector distributions. The starting point of this procedure is...

Mar
01
2007

Motivic Cohomology

Bass' NK Groups and cdh-Fibrant Hochschild Homology
11:00am|S-101

By definition, NK_0(R) is K_0(R[t]) modulo K_0(R). We give a formula for this group when R is of finite type over a field of characteristic zero. The group is bigraded and determined by its typical pieces, which are the cdh cohomology groups H^p(R...

Feb
22
2007

Motivic Cohomology

Arithmetic Cohomology and Special Values of Zeta-Functions (after Geisser)
11:00am|S-101

Geisser gives conjectured formulas for special values of zeta-functions of varieties over finite fields in terms of Euler characteristics of arithmetic cohomology (an improved version of Weil-etale cohomology). He then proves these formulas under...