On the Universal Curves with Unordered Marked Points

Fuente: arXiv
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Main Authors: Watanabe, Tatsunari, Luo, Ma
Format: Preprint
Published: 2025
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author Watanabe, Tatsunari
Luo, Ma
author_facet Watanabe, Tatsunari
Luo, Ma
contents Over any field of characteristic $0$, we prove that the homotopy exact sequence of algebraic fundamental groups for the universal curve with unordered marked points does not split. The same nonsplitting holds for the universal hyperelliptic curve. Our approach extends Chen's topological result to the profinite setting and relies on the use of relative and continuous relative completions to detect the nonexistence of algebraic sections.
format Preprint
id arxiv_https___arxiv_org_abs_2511_12354
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the Universal Curves with Unordered Marked Points
Watanabe, Tatsunari
Luo, Ma
Algebraic Geometry
Algebraic Topology
Over any field of characteristic $0$, we prove that the homotopy exact sequence of algebraic fundamental groups for the universal curve with unordered marked points does not split. The same nonsplitting holds for the universal hyperelliptic curve. Our approach extends Chen's topological result to the profinite setting and relies on the use of relative and continuous relative completions to detect the nonexistence of algebraic sections.
title On the Universal Curves with Unordered Marked Points
topic Algebraic Geometry
Algebraic Topology
url https://arxiv.org/abs/2511.12354