English

2-Nilpotent Real Section Conjecture

Algebraic Geometry 2013-05-22 v3 Algebraic Topology

Abstract

We show a 2-nilpotent section conjecture over R: for a geometrically connected curve X over R such that each irreducible component of its normalization has R-points, pi_0(X(R)) is determined by the maximal 2-nilpotent quotient of the fundamental group with its Galois action, as the kernel of an obstruction of Jordan Ellenberg. This implies that for X smooth and proper, X(R)^{+/-} is determined by the maximal 2-nilpotent quotient of Gal(C(X)) with its Gal(R)-action, where X(R)^{+/-} denotes the set of real points equipped with a real tangent direction, showing a 2-nilpotent birational real section conjecture.

Keywords

Cite

@article{arxiv.1006.0265,
  title  = {2-Nilpotent Real Section Conjecture},
  author = {Kirsten Wickelgren},
  journal= {arXiv preprint arXiv:1006.0265},
  year   = {2013}
}

Comments

24 pages, 1 figure. To appear Mathematiche Annalen

R2 v1 2026-06-21T15:30:44.818Z