{ "id": "2402.15329", "version": "v2", "published": "2024-02-23T13:53:58.000Z", "updated": "2024-03-14T15:45:59.000Z", "title": "Iterations of the functor of naive $\\mathbb A^1$-connected components of varieties", "authors": [ "Nidhi Gupta" ], "comment": "10 pages, comments are welcome, v2: added subsection 4.3", "categories": [ "math.AG" ], "abstract": "For any sheaf of sets $\\mathcal F$ on $Sm/k$, it is well known that the universal $\\mathbb A^1$-invariant quotient of $\\mathcal F$ is given as the colimit of sheaves $\\mathcal S^n(\\mathcal F)$ where $\\mathcal S(F)$ is the sheaf of naive $\\mathbb A^1$-connected components of $\\mathcal F$. We show that these infinite iterations of naive $\\mathbb A^1$-connected components in the construction of universal $\\mathbb A^1$-invariant quotient for a scheme are certainly required. For every $n$, we construct an $\\mathbb A^1$-connected variety $X_n$ such that $\\mathcal S^n(X_n)\\neq \\mathcal S^{n+1}(X_n)$ and $\\mathcal S^{n+2}(X_n)=*$.", "revisions": [ { "version": "v2", "updated": "2024-03-14T15:45:59.000Z" } ], "analyses": { "subjects": [ "14F42" ], "keywords": [ "connected components", "invariant quotient", "infinite iterations", "construction" ], "note": { "typesetting": "TeX", "pages": 10, "language": "en", "license": "arXiv", "status": "editable" } } }