14
votes
0answers
369 views
Octonions and the Fano plane.
Does the Fano plane mnemonic for octonion multiplication have any deeper meaning?
http://upload.wikimedia.org/wikipedia/commons/2/2d/FanoPlane.svg
The symmetry group of the Fano …
1
vote
1answer
193 views
A “Riemannian” analogue of Kobayashi metric?
Recall that Kobayashi metric is defined on any complex manifold $M$. This is a pseudo-metric according to which a tangent vector $v$ at $P$ has length at most $1$ if there is hol …
1
vote
0answers
140 views
Non-compact Riemann surfaces and affine algebraic curves
Is every connected non-compact Riemann surface biholomorphically equivalent to an affine algebraic curve in some ${\mathbb C}^n$? I suspect that surfaces of infinite genus probably …
0
votes
1answer
79 views
Trivial Line Bundle-Riemann surfaces
What are the Hermitian metrics in a trivial line bundle on a Riemann surface X?
I read that a Hermitian metric in the trivial line bundle is equivalent to a $\mathcal{C}^{\infty}$ …
2
votes
3answers
299 views
Hyperbolic Riemann Surface
Let $X$ be a compact Riemann surface and $x\in X$.
Is $X - \overline{D(x,r_x)}$ hyperbolic?
1
vote
1answer
50 views
Computing saddle connections in flat structures
Background: A polygonal billiards table $P$ with rational angles gives rise to a flat structure $S(P)$ in a standard way, described here. Curves of constant argument on $S(P)$ whic …
1
vote
1answer
77 views
Green’s function - Hyperbolic Riemann surface
A Riemann surface is said to be:
-Potential-theoretically hyperbolic if it has a non-constant bounded subharmonic function.
-Poincaré hyperbolic if it is covered by the unid disk …
1
vote
0answers
135 views
Complete curves in $M_g$ and Theta Characteristics
Let $g\geq 3$. Following the reference below, the locus of curves in $M_g$ with an effective even theta characteristic has codimension $1$. (Those are the curves $C$ with an effect …
2
votes
1answer
80 views
Finiteness theorem for first-cohomology group of sheaf of holomorphic functions on compact Riemann surfaces
I have been reading Otto Forster's Lectures on Riemann Surfaces recently, and came across a question on section 15, Finiteness Theorem, which asserts that $H^1(X, \mathcal{O})$ is …
1
vote
1answer
179 views
A question from Otto Forster’s book on Riemann surfaces
I am reading section 14, A Finiteness Theorem of Otto Forster's book Lectures on Riemann Surfaces, and come across a problem on Theorem 14.15 on page 117. In the proof Forster intr …
15
votes
0answers
276 views
On Determinants of Laplacians on Riemann Surfaces
History of the Formula: In their famous paper "On Determinants of Laplacians on Riemann Surfaces" (1986), D'Hoker and Phong computed the determinant of the Laplacian $\Delta_n^+$ o …
4
votes
2answers
328 views
The existence of meromorphic functions on Riemann surfaces
In Miranda's book on algebraic curves and Riemann surfaces, Miranda writes:
It is a basic and highly nontrivial
result that a compact Riemann surface
has nonconstant meromo …
12
votes
3answers
673 views
Injective morphism from curves to $\mathbb CP^2$
Is there a smooth compact complex curve that does not admit an injective holomorphic map to $\mathbb CP^2$ ? Let me stress, that the image of the curve in $\mathbb CP^2$ can have s …
8
votes
1answer
201 views
Injective morphism from an elliptic curve to $\mathbb CP^2$.
Let $E$ be the elliptic curve $x^3+y^3+z^3=0$.
Question. Are there injective morphisms $E\to \mathbb CP^2$ of arbitrary high degree?
Comments. 1) There are injective morphisms $ …
0
votes
2answers
156 views
Fuchsian groups and automorphisms of Riemann surfaces
Let $\Gamma \subseteq PSL_2(\mathbb{R})$ be a Fuchsian group, possibly containing elliptic elements. Is it true that $N(\Gamma) / \Gamma$, where $N(\Gamma)$ the normalizer of $\Gam …

