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Related papers: Relative $\mathbb{A}^1$-homology and its applicati…

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Given a CW-complex A we define an `A-shaped' homology theory which behaves nicely towards A-homotopy groups allowing the generalization of many classical results. We also develop a relative version of the Federer spectral sequence for…

Algebraic Topology · Mathematics 2014-05-12 Miguel Ottina

We survey some topics in ${\mathbb A}^1$-homotopy theory. Our main goal is to highlight the interplay between ${\mathbb A}^1$-homotopy theory and affine algebraic geometry, focusing on the varieties that are "contractible" from various…

Algebraic Geometry · Mathematics 2019-03-20 Aravind Asok , Paul Arne Østvær

We define a new version of $\mathbb A^1$-homology, called cellular $\mathbb A^1$-homology, for smooth schemes over a field that admit an increasing filtration by open subschemes with cohomologically trivial closed strata. We provide several…

Algebraic Geometry · Mathematics 2023-06-29 Fabien Morel , Anand Sawant

We establish a relative version of the abstract "affine representability" theorem in ${\mathbb A}^1$--homotopy theory from Part I of this paper. We then prove some ${\mathbb A}^1$--invariance statements for generically trivial torsors under…

Algebraic Geometry · Mathematics 2018-03-16 Aravind Asok , Marc Hoyois , Matthias Wendt

We prove that a smooth scheme of dimension $n$ over a perfect field is A^1-weakly equivalent to a point if it is A^1-n-connected. We also prove an excision result for A^1-homotopy sheaves over a perfect field.

Algebraic Geometry · Mathematics 2018-09-07 Yuri Shimizu

In this paper, we study $\mathbb{A}^1$-connected varieties from log geometry point of view, and prove a criterion for $\mathbb{A}^1$-connectedness. As applications, we provide many interesting examples of $\mathbb{A}^1$-connected varieties…

Algebraic Geometry · Mathematics 2017-02-21 Qile Chen , Yi Zhu

We establish a general "affine representability" result in ${\mathbb A}^1$-homotopy theory over a general base. We apply this result to obtain representability results for vector bundles in ${\mathbb A}^1$-homotopy theory. Our results…

Algebraic Geometry · Mathematics 2017-10-18 Aravind Asok , Marc Hoyois , Matthias Wendt

We study two different flavours of A^1-homotopy theory in the setting of spectral algebraic geometry, and compare them to classical A^1-homotopy theory. As an application we show that the spectral analogue of Weibel's homotopy invariant…

Algebraic Topology · Mathematics 2020-10-16 Denis-Charles Cisinski , Adeel A. Khan

We prove analogs of Whitehead's theorem (from algebraic topology) for both the Chow groups and for the Grothendieck group of coherent sheaves: a morphism between smooth projective varieties whose pushforward is an isomorphism on the Chow…

Algebraic Geometry · Mathematics 2021-03-04 Eoin Mackall

We introduce a new homology theory of uniform spaces, provisionally called $\mu$-homology theory. Our homology theory is based on hyperfinite chains of microsimplices. This idea is due to McCord. We prove that $\mu$-homology theory…

Algebraic Topology · Mathematics 2018-12-04 Takuma Imamura

We investigate the relationship between smoothness and the relative global dimension of a ring extension. We prove that a smooth commutative algebra $A$ over $B$ has finite relative global dimension $\text{gdim}(A,B)$. Conversely, under a…

Commutative Algebra · Mathematics 2025-11-03 Kostiantyn Iusenko , Eduardo do Nascimento Marcos , Victor do Valle Pretti

In this paper, we introduce and study representation homology of topological spaces, which is a natural homological extension of representation varieties of fundamental groups. We give an elementary construction of representation homology…

Algebraic Topology · Mathematics 2020-02-25 Yuri Berest , Ajay C. Ramadoss , Wai-kit Yeung

We show that $\mathbb A^1$-connectedness of a large class of varieties over a field $k$ can be characterized as the condition that their generic point can be connected to a $k$-rational point using (not necessarily naive) $\mathbb…

Algebraic Geometry · Mathematics 2021-08-20 Chetan Balwe , Amit Hogadi , Anand Sawant

For each elliptic curve A over the rational numbers we construct a 2-periodic S^1-equivariant cohomology theory E whose cohomology ring is the sheaf cohomology of A; the homology of the sphere of the representation z^n is the cohomology of…

Algebraic Topology · Mathematics 2007-05-23 J. P. C. Greenlees

We start to study the problem of classifying smooth proper varieties over a field k from the standpoint of A^1-homotopy theory. Motivated by the topological theory of surgery, we discuss the problem of classifying up to isomorphism all…

Algebraic Geometry · Mathematics 2011-04-15 Aravind Asok , Fabien Morel

Higher homological algebra, basically done in the framework of an $n$-cluster tilting subcategory $\mathcal{M}$ of an abelian category $\mathcal{A}$, has been the topic of several recent researches. In this paper, we study a relative…

Rings and Algebras · Mathematics 2023-11-13 Rasool Hafezi , Javad Asadollahi , Yi Zhang

We provide an expository introduction to $\mathbb{A}^1$-enumerative geometry, which uses the machinery of $\mathbb{A}^1$-homotopy theory to enrich classical enumerative geometry questions over a broader range of fields. Included is a…

Algebraic Geometry · Mathematics 2020-07-21 Thomas Brazelton

Taking a representation-theoretic viewpoint, we construct a continuous associahedron motivated by the realization of the generalized associahedron in the physical setting. We show that our associahedron shares important properties with the…

Representation Theory · Mathematics 2025-12-02 Maitreyee C. Kulkarni , Jacob P. Matherne , Kaveh Mousavand , Job D. Rock

We study some properties of A^1-homotopy groups: geometric interpretations of connectivity, excision results, and a re-interpretation of quotients by free actions of connected solvable groups in terms of covering spaces in the sense of…

Algebraic Geometry · Mathematics 2009-03-09 Aravind Asok , Brent Doran

We extend some basic results from the singular homology theory of topological spaces to the setting of \v{C}ech's closure spaces. We prove analogues of the excision and Mayer-Vietoris theorems and the Hurewicz theorem in dimension one. We…

Algebraic Topology · Mathematics 2025-02-20 Nikola Milićević
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