$\mathbb A^1$-connected components of affine quadrics

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Authors: Chetan Balwe, Nidhi Gupta
Cited by: 0

Abstract

For any smooth quadratic hypersurface $X$ in $\mathbb A^n_k$, we use the iterations of the functor of naive $\mathbb{A}^1$-connected components $\mathcal{S}$ to study the field-valued sections of the sheaf of $\mathbb{A}^1$-connected components $π_0^{\mathbb{A}^1}(X)$ of $X$. We prove that for any field $F/k$, the canonical isomorphism $π_0^{\mathbb{A}^1}(X)(F) \xrightarrow{\sim} \lim_{n} \mathcal{S}^n(X)(F)$ stabilizes at $n=2$, meaning that $π_0^{\mathbb{A}^1}(X)(F)=\mathcal{S}^2(X)(F)$. Furthermore, by combining this result with Morel's characterization of $\mathbb{A}^1$-connected spaces in terms of the triviality of field-valued sections of $π_0^{\mathbb{A}^1}$, we provide a complete characterization of $\mathbb{A}^1$-connected smooth quadratic hypersurfaces in $\mathbb{A}^n_k$.

Fields of Study & Subjects

Algebraic Geometry and Number Theory Homotopy and Cohomology in Algebraic Topology Advanced Algebra and Geometry

Publication details

Journal / source
arXiv (Cornell University)
Publication date
28 January 2026
Document type
Preprint