activity
20092026
most citedA cohomological classification of vector bundles on smooth affine threefolds

53 citations · 322 across the 36 of their papers we have counts for

collaborators

45 papers

math.AG2026

Vector bundles on singular surfaces and threefolds

Jean Fasel, Maria Yakerson

We fully classify vector bundles of critical rank on normal affine surfaces and threefolds over algebraically closed fields via their Chern classes. We also prove existence of rank…

math.AG2026

Suslin's cancellation conjecture on smooth real affine varieties with few real points

Sourjya Banerjee, Jean Fasel, Samuel Lerbet

We study Suslin's cancellation conjecture on smooth real affine varieties whose real locus is empty or, more generally, of small cohomological dimension.

math.AG2026

Exotic Hopf maps, weight shifting and applications to vector bundles

Jean Fasel, William Hornslien

Using motivic homotopy theory we produce several explicit polynomial representatives of the suspension of the Hopf map defined over the integers. We derive from this computation an…

math.AG2025

Splitting vector bundles over real algebraic varieties

Aravind Asok, Jean Fasel, Samuel Lerbet

Suppose is a smooth affine real variety and is a vector bundle over . We analyze the problem of splitting off a free rank one summand from in cor…

math.KT2024

Quadratic Riemann-Roch formulas

Frédéric Déglise, Jean Fasel

In this article, we produce Grothendieck-Riemann-Roch formulas for cohomology theories that are not oriented in the classical sense. We then specialize to the case of cohomology th…

math.AG2023

On Tate Milnor-Witt Motives

Jean Fasel, Nanjun Yang

Smooth projective -varieties with isolated rational fixed points admit Tate Milnor-Witt motives. Over Euclidean fields, we give a splitting formula of such motives, w…

math.KT2021

Formal ternary laws and Buchstaber's 2-groups

David Coulette, Frédéric Déglise, Jean Fasel +1

We develop the algebraic formalism of the formal ternary laws of C. Walter and we compare them to Buchstaber's 2-valued formal group laws. We also compute the "elementary" formal t…

math.AG2021

Vector bundles on algebraic varieties

Aravind Asok, Jean Fasel

We survey some recent progress in the theory of vector bundles on algebraic varieties and related questions in algebraic K-theory.

math.AG2021

Suslin's cancellation conjecture in the smooth case

Jean Fasel

We prove that stably isomorphic vector bundles of rank d-1 on a smooth affine d-fold X over an algebraically closed field k are indeed isomorphic, provided d! is invertible in k. T…

math.AG2020★ 2 cited

Algebraic vector bundles and -local A^1-homotopy theory

Aravind Asok, Jean Fasel, Michael J. Hopkins

Using techniques of A^1-homotopy theory, we produce motivic lifts of elements in classical homotopy groups of spheres; these lifts provide polynomial maps of spheres and allow us t…

math.AG2020★ 11 cited

On the rational motivic homotopy category

Frédéric Déglise, Jean Fasel, Adeel A. Khan +1

We study the structure of the rational motivic stable homotopy category over general base schemes. Our first class of results concerns the six operations: we prove absolute purity,…

math.KT2020★ 3 cited

The stable Adams operations on Hermitian K-theory

Jean Fasel, Olivier Haution

We prove that exterior powers of (skew-)symmetric bundles induce a -ring structure on the ring , when is a scheme where is invertible. Using this…

math.AG2020

Milnor-Witt Motives

Tom Bachmann, Baptiste Calmès, Frédéric Déglise +2

We develop the theory of Milnor-Witt motives and motivic cohomology. Compared to Voevodsky's theory of motives and his motivic cohomology, the first difference appears in our defin…

math.KT2019

Lectures on Chow-Witt groups

Jean Fasel

In these lectures, we provide a toolkit to work with Chow-Witt groups, and more generally with the homology and cohomology of the Rost-Schmid complex associated to Milnor-Witt -…

math.AG2019

Localization and nilpotent spaces in A^1-homotopy theory

Aravind Asok, Jean Fasel, Michael J. Hopkins

For a subring of the rational numbers, we study -localization functors in the local homotopy theory of simplicial presheaves on a small site and then in -homo…

math.AG2019

The Borel character

Frédéric Déglise, Jean Fasel

The main purpose of this article is to define a quadratic analog of the Chern character, the so-called Borel character, which identifies rational higher Grothendieck-Witt groups wi…

math.AG2019★ 2 cited

Borel isomorphism and absolute purity

Frédéric Déglise, Jean Fasel, Fangzhou Jin +1

We prove absolute purity for the rational motivic sphere spectrum. The main ingredient is the construction of an analogue of the Chern character, where algebraic K-theory is replac…

cs.IT2019

Rank weights for arbitrary finite field extensions

Grégory Berhuy, Jean Fasel, Odile Garotta

In this paper, we study several definitions of generalized rank weights for arbitrary finite extensions of fields. We prove that all these definitions coincide, generalizing known…

math.KT2018

Motivic spheres and the image of the Suslin--Hurewicz map

Aravind Asok, Jean Fasel, Ben Williams

We show that an old conjecture of A.A. Suslin characterizing the image of a Hurewicz map from Quillen K-theory in degree to Milnor K-theory in degree admits an interpretati…

math.KT2017★ 21 cited

On the effectivity of spectra representing motivic cohomology theories

Tom Bachmann, Jean Fasel

Let k be an infinite perfect field. We provide a general criterion for a spectrum in the stable homotopy category over k to be effective, i.e. to be in the localizing subcategory g…

math.KT2017★ 18 cited

The Milnor-Witt motivic ring spectrum and its associated theories

Frédéric Déglise, Jean Fasel

We build a ring spectrum representing Milnor-Witt motivic cohomology, as well as its étale local version and show how to deduce out of it three other theories: Borel-Moore homology…

math.KT2017★ 7 cited

A comparison theorem for MW-motivic cohomology

Baptiste Calmès, Jean Fasel

We prove that for a finitely generated field over an infinite perfect field k, and for any integer n, the (n,n)-th MW-motivic cohomology group identifies with the n-th Milnor-Witt…

math.KT2017★ 15 cited

A cancellation theorem for Milnor-Witt correspondences

Jean Fasel, Paul Arne Østvær

We show that finite Milnor-Witt correspondences satisfy a cancellation theorem with respect to the pointed multiplicative group scheme. This has several notable applications in the…

math.KT2017★ 20 cited

MW-motivic complexes

Frédéric Déglise, Jean Fasel

The aim of this work is to develop a theory parallel to that of motivic complexes based on cycles and correspondences with coefficients in quadratic forms. This framework is closer…