# Tagged Questions

**2**

votes

**0**answers

98 views

### when is an irreducible SL_2(C) representation of a cusped hyperbolic 3-manifold scheme reduced or smooth

Let $M$ be an orientable cusped hyperbolic 3-manifold. Let $\rho \in hom(\pi_1(M),SL_2(\mathbb{C}))$ be an irreducible representation.
Is $\rho$ scheme reduced ?
What can prevent $\rho$ from being ...

**9**

votes

**6**answers

1k views

### Is there a good notion of morphism between orbifolds?

Following Thurston, an orbifold is a topological space which looks locally like a finite quotient of $\mathbb R^n$ by a finite group of $O(n)$: this is expressed using charts as for differentiable ...

**0**

votes

**0**answers

151 views

### Casson's invariant and intersection homology

EDIT: Immediately after I wrote this question, I remembered the elegant paper "An intersection homology invariant for knots in a rational homology 3-sphere" by Frohman and Nicas, which I believe does ...

**0**

votes

**0**answers

63 views

### algebraicness of trace field of finite volume hyperbolic 3-manifold and dimension of $SL(2,C)$-character variety

Does the following statement
"Let $G$ be a finitely generated
group and let $X(G)$ be the
$SL(2,\mathbb{C})$ character variety
of $G$. If $X(G)$ contains an
irreducible component $X_0$ ...

**15**

votes

**1**answer

451 views

### Can the SL_2 character variety of a three-manifold be nonreduced?

Let $M^3$ be a three-manifold and consider the representation variety and the character variety of $M$:
$$Y=\operatorname{Hom}(\pi_1(M^3),\operatorname{SL}(2,\mathbb C))$$
...

**5**

votes

**5**answers

977 views

### What is the possible usefulness of étale topology and cohomology apart from the resolution of the Weil conjecture ?

My question is as stated in the title:
What is the possible usefulness of étale topology and cohomology apart from the resolution of the Weil conjecture ?
I am particularly interested to know if ...

**3**

votes

**0**answers

292 views

### What is the behaviour of a smooth 3-manifold acting by a circle?

As Mumford pointed out in his paper 'Topology of Normal Singularities and a Criterion for Simplicity'(1961), every point $p$ on a normal complex surface $V$ has an associated 3-manifold $M$ which is ...