Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userA quadratic refinement of the Grothendieck-Lefschetz-Verdier trace formula
172
0
0.0
(
0
)
Authors
Marc Hoyois
Ask ChatGPT about the research
No Arabic abstract
We prove a trace formula in stable motivic homotopy theory over a general base scheme, equating the trace of an endomorphism of a smooth proper scheme with the Euler characteristic integral of a certain cohomotopy class over its scheme of fixed points. When the base is a field and the fixed points are etale, we compute this integral in terms of Morels identification of the ring of endomorphisms of the motivic sphere spectrum with the Grothendieck-Witt ring. In particular, we show that the Euler characteristic of an etale algebra corresponds to the class of its trace form in the Grothendieck-Witt ring.
rate research
Read More
We study the 0-th stable A^1-homotopy sheaf of a smooth proper variety over a field k assumed to be infinite, perfect and to have characteristic unequal to 2. We provide an explicit description of this sheaf in terms of the theory of (twisted) Chow-Witt groups as defined by Barge-Morel and developed by Fasel. We study the notion of rational point up to stable A^1-homotopy, defined in terms of the stable A^1-homotopy sheaf of groups mentioned above. We show that, for a smooth proper k-variety X, existence of a rational point up to stable A^1-homotopy is equivalent to existence of a 0-cycle of degree 1.
We establish a Grothendieck--Lefschetz theorem for smooth ample subvarieties of smooth projective varieties over an algebraically closed field of characteristic zero and, more generally, for smooth subvarieties whose complement has small cohomological dimension. A weaker statement is also proved in a more general context and in all characteristics. Several applications are included.
We announce recent results on a connection between factorization statistics of polynomials over a finite field and the structure of the cohomology of configurations in $mathbb{R}^3$ as a representation of the symmetric group. This connection parallels a result of Church, Ellenberg, and Farb relating factorization statistics of squarefree polynomials and the cohomology of configurations in $mathbb{R}^2$.
Let Sigma denote the prismatization of Spf (Z_p). The multiplicative group over Sigma maps to the prismatization of the multiplicative group over Spf (Z_p). We prove that the kernel of this map is the Cartier dual of some 1-dimensional formal group over Sigma. We obtain some results about this formal group (e.g., we describe its Lie algebra). We give a very explicit description of the pullback of the formal group to the quotient of the q-de Rham prism by the action of the multiplicative group of Z_p.
In this short paper we outline (mostly without proofs) our new approach to the derived category of sheaves of commutative DG rings. The proofs will appear in a subsequent paper. Among other things, we explain how to form the derived intersection of two closed subschemes inside a given algebraic scheme X, without recourse to simplicial or higher homotopical methods, and without any global assumptions on X.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
