2006/11/05 by Hélène Esnault, Esnault, Hélène, Phùng Hô Hái +1
Mathematics · #Algebraic Geometry (math.AG) #Algebraic Geometry and Number Theory #FOS: Mathematics #Number Theory (math.NT)
paper · pdf · doi:10.48550/arxiv.math/0611115
openalex publication_date 2006/11/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We define a linear structure on Grothendieck's arithmetic fundamental group π1(X, x) of a scheme X defined over a field k of characteristic 0. It allows us to link the existence of sections of the Galois group \rm Gal( k/k) to π1(X, x) with the existence of a neutral fiber functor on the category which linearizes it. When applied to Grothendieck section conjecture, it allows us to find a k-structure on the universal covering, and k-rational pro-points at finite and infinite distance which lift given k-rational points. Changes as compared to the first version: (some) typos corrected, english impoved (?), (2.6) better explained, Thm 3.2, 3) made more precise, correspondingly Cor. 4.6 made more precise as well. It equates conjugacy classes of sections with neutral fiber functors. Finally Thm 5.1 establishes a bijection between rational points and neutral fiber functors under the assumption that Grothendieck's conjecture is true.