1. CMB Online first
 Iena, Oleksandr; Leytem, Alain

On the singular sheaves in the fine Simpson moduli spaces of $1$dimensional sheaves
In the Simpson moduli space $M$ of semistable sheaves with
Hilbert polynomial $dm1$ on a projective plane we study the
closed subvariety $M'$ of sheaves that are not locally free on
their support. We show that for $d\ge 4$ it is a singular subvariety
of codimension $2$ in $M$. The blow up of $M$ along $M'$ is interpreted
as a (partial) modification of $M\setminus M'$ by line bundles
(on support).
Keywords:Simpson moduli spaces, coherent sheaves, vector bundles on curves, singular sheaves Category:14D20 

2. CMB 2008 (vol 51 pp. 519)
 Coskun, Izzet; Harris, Joe; Starr, Jason

The Effective Cone of the Kontsevich Moduli Space
In this paper we prove that the cone of effective divisors on the
Kontsevich moduli spaces of stable maps, $\Kgnb{0,0}(\PP^r,d)$,
stabilize when $r \geq d$. We give a complete characterization of the
effective divisors on $\Kgnb{0,0}(\PP^d,d)$. They are nonnegative
linear combinations of boundary divisors and the divisor of maps with
degenerate image.
Categories:14D20, 14E99, 14H10 

3. CMB 2007 (vol 50 pp. 427)
 Mejía, Israel Moreno

On the Image of Certain Extension Maps.~I
Let $X$ be a smooth complex projective curve of genus $g\geq
1$. Let $\xi\in J^1(X)$ be a line bundle on $X$ of degree $1$. Let
$W=\Ext^1(\xi^n,\xi^{1})$ be the space of extensions of $\xi^n$
by $\xi^{1}$. There is a rational map
$D_{\xi}\colon G(n,W)\rightarrow SU_{X}(n+1)$,
where $G(n,W)$ is the Grassmannian variety of $n$linear subspaces
of $W$ and $\SU_{X}(n+1)$ is the moduli space of rank $n+1$ semistable
vector
bundles on $X$ with trivial determinant. We prove that if $n=2$,
then $D_{\xi}$ is
everywhere defined and is injective.
Categories:14H60, 14F05, 14D20 

4. CMB 2005 (vol 48 pp. 90)
 Jeffrey, Lisa C.; Mare, AugustinLiviu

Products of Conjugacy Classes in $SU(2)$
We obtain a complete description of the conjugacy classes
$C_1,\dots,C_n$ in $SU(2)$ with the property that $C_1\cdots
C_n=SU(2)$. The basic instrument is a characterization of the
conjugacy classes $C_1,\dots,C_{n+1}$ in $SU(2)$ with $C_1\cdots
C_{n+1}\ni I$, which generalizes a result of \cite{JeWe}.
Categories:14D20, 14P05 

5. CMB 2002 (vol 45 pp. 417)
 Kamiyama, Yasuhiko; Tsukuda, Shuichi

On Deformations of the Complex Structure on the Moduli Space of Spatial Polygons
For an integer $n \geq 3$, let $M_n$ be the moduli space of spatial polygons
with $n$ edges. We consider the case of odd $n$. Then $M_n$ is a Fano
manifold of complex dimension $n3$. Let $\Theta_{M_n}$ be the
sheaf of germs of holomorphic sections of the tangent bundle
$TM_n$. In this paper, we prove $H^q (M_n,\Theta_{M_n})=0$ for all
$q \geq 0$ and all odd $n$. In particular, we see that the moduli
space of deformations of the complex structure on $M_n$ consists of
a point. Thus the complex structure on $M_n$ is locally rigid.
Keywords:polygon space, complex structure Categories:14D20, 32C35 

6. CMB 2000 (vol 43 pp. 174)
7. CMB 2000 (vol 43 pp. 162)
 Foth, Philip

Moduli Spaces of Polygons and Punctured Riemann Spheres
The purpose of this note is to give a simple combinatorial
construction of the map from the canonically compactified moduli
spaces of punctured complex projective lines to the moduli spaces
$\P_r$ of polygons with fixed side lengths in the Euclidean space
$\E^3$. The advantage of this construction is that one can obtain a
complete set of linear relations among the cycles that generate
homology of $\P_r$. We also classify moduli spaces of pentagons.
Categories:14D20, 18G55, 14H10 

8. CMB 1999 (vol 42 pp. 307)
 Kapovich, Michael; Millson, John J.

On the Moduli Space of a Spherical Polygonal Linkage
We give a ``wallcrossing'' formula for computing the topology of
the moduli space of a closed $n$gon linkage on $\mathbb{S}^2$.
We do this by determining the Morse theory of the function
$\rho_n$ on the moduli space of $n$gon linkages which is given by
the length of the last sidethe length of the last side is
allowed to vary, the first $(n  1)$ sidelengths are fixed. We
obtain a Morse function on the $(n  2)$torus with level sets
moduli spaces of $n$gon linkages. The critical points of $\rho_n$
are the linkages which are contained in a great circle. We give a
formula for the signature of the Hessian of $\rho_n$ at such a
linkage in terms of the number of backtracks and the winding
number. We use our formula to determine the moduli spaces of all
regular pentagonal spherical linkages.
Categories:14D20, 14P05 
