All Questions
5 questions
14
votes
3
answers
1k
views
Can we define homotopy groups using Tannakian categories
This is another vague question. Hope you guys don't mind.
Let $T$ be a Tannakian category. For any fibre functor $F$ on $T$ we define the fundamental group of $T$ at $F$, denoted by $\pi_1(T,F)$, to ...
8
votes
1
answer
813
views
Inverse galois problem and étale homotopy
Is there any relation between étale homotopy theory (Grothendieck-Galois theory) and the inverse Galois problem?...I mean...in classical homotopy theory, every finite group $G$ realizes as a "Galois ...
3
votes
1
answer
321
views
A complex variety with a finite non-abelian simple fundamental group
Does there exist a complex smooth proper variety whose fundamental group is finite non-abelian simple?
3
votes
1
answer
1k
views
The (topological) fundamental group of (quasi)-projective algebraic varieties
I would like to know:
What does the fundamental group of a quasi-projective algebraic variety look like?
I remember that I have seen somewhere that for a connected, finite-type CW-complex $X$, ...
2
votes
0
answers
111
views
Is the connecting map $\pi_2(B) \to \pi_1(F)$ ever nonzero in smooth proper families?
Suppose that $X, B$ are smooth irreducible varieties over $\mathbb{C}$ and $f : X \to B$ is a smooth proper morphism. Then we can consider the homotopy exact sequence:
$$ \pi_2(B) \to \pi_1(F) \to \...