Tagged Questions

1
vote
1answer
164 views

Field of definition of a finite etale cover of an anabelian curve

Let $X$ be an anabelian curve over a number field $K$ and let $p:Y\rightarrow X$ be a finite etale cover. Then is anything known (or has anything been conjectured) about the field …
7
votes
2answers
754 views

What conjectures in anabelian geometry are false?

Proving things suspected to be true in anabelian geometry is usually very hard. Maybe it is easier to disprove things suspected to be false? In particular, I am interested in fals …
5
votes
0answers
239 views

discretifications of the fundamental group functor

Grothendieck calls a "discretification" of a profinite group $\hat G$, a discrete group $G$ whose profinite completion is isomorphic to $\hat G$. Does Grothendieck also define a …
16
votes
1answer
497 views

Why does the Section Conjecture exclude curves of genus 1?

Let $X$ be an integral proper normal curve over a (perfect) field $F$, of genus $\geq 2$. One variant of Grothendieck's "section conjecture" states that the sections $G_F \rightarr …
12
votes
2answers
2k views

Why should the anabelian geometry conjectures be true?

I had probed friends of mine about Grothendieck's motivation for making the anabelian geometry conjectures, and they gave me the following explanation: If $X$ is a hyperbolic curv …
7
votes
2answers
507 views

Exotic automorphisms of the fundamental group of a curve?

A while back, J. Ellenberg brought the following problem to my attention. If $G$ is a residually finite group, let $\widehat G$ be its profinite completion. Let $S$ be a closed su …