Profinite Groups with a Cyclotomic $p$-Orientation
Documenta mathematica, Tome 25 (2020), pp. 1881-1916
Let p be a prime. A continuous representation θ:G→GL1(Zp) of a profinite group G is called a cyclotomic p-orientation if for all open subgroups U⊆G and for all k,n≥1 the natural maps Hk(U,Zp(k)/pn)→Hk(U,Zp(k)/p) are surjective. Here Zp(k) denotes the Zp-module of rank 1 with U-action induced by θ∣Uk. By the Rost-Voevodsky theorem, the cyclotomic character of the absolute Galois group GK of a field K is, indeed, a cyclotomic p-orientation of GK. We study profinite groups with a cyclotomic p-orientation. In particular, we show that cyclotomicity is preserved by several operations on profinite groups, and that Bloch-Kato pro-p groups with a cyclotomic p-orientation satisfy a strong form of Tits' alternative and decompose as semi-direct product over a canonical abelian closed normal subgroup.
Classification :
12F10, 12G05, 20E18
Mots-clés : absolute Galois groups, Rost-Voevodsky theorem, elementary type conjecture
Mots-clés : absolute Galois groups, Rost-Voevodsky theorem, elementary type conjecture
@article{10_4171_dm_788,
author = {Claudio Quadrelli and Thomas S. Weigel},
title = {Profinite {Groups} with a {Cyclotomic} $p${-Orientation}},
journal = {Documenta mathematica},
pages = {1881--1916},
year = {2020},
volume = {25},
doi = {10.4171/dm/788},
url = {http://geodesic.mathdoc.fr/articles/10.4171/dm/788/}
}
Claudio Quadrelli; Thomas S. Weigel. Profinite Groups with a Cyclotomic $p$-Orientation. Documenta mathematica, Tome 25 (2020), pp. 1881-1916. doi: 10.4171/dm/788
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