Tame approximation conjecture for Grunwald realizations

From papers

Let GG be a finite group and let SS be a finite set of places of Q\mathbf{Q}, none dividing G|G|. For each vSv\in S, let Fv/QvF_v/\mathbf{Q}_v be a Galois extension equipped with an embedding

Gal(Fv/Qv)G.\operatorname{Gal}(F_v/\mathbf{Q}_v)\hookrightarrow G.

Tame approximation conjecture. There exists a Galois extension L/QL/\mathbf{Q} such that

Gal(L/Q)G\operatorname{Gal}(L/\mathbf{Q})\cong G

and

LvFvdeg(L)/deg(Fv)L_v\cong F_v^{\oplus\deg(L)/\deg(F_v)}

for every vSv\in S. This is a tame form of the Grunwald problem: local extensions should be simultaneously realized by a global extension with the prescribed Galois group. The supplied text describes related positive results for supersolvable groups and notes unresolved difficulties in general, so the conjecture remains open.

Progress summary

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Sources & referencesView supporting material

Primary source

Santiago Arango-Piñeros, Sam Frengley and Sameera Vemulapalli, “Galois groups of simple abelian varieties over finite fields and exceptional Tate classes”, arXiv:2505.09589 (2025).

Solutions 0

No solutions have been posted yet.