7,029 research outputs found
Uniformization of Deligne-Mumford curves
We compute the fundamental groups of non-singular analytic Deligne-Mumford
curves, classify the simply connected ones, and classify analytic
Deligne-Mumford curves by their uniformization type. As a result, we find an
explicit presentation of an arbitrary Deligne-Mumford curve as a quotient
stack. Along the way, we compute the automorphism 2-groups of weighted
projective stacks . We also discuss connections
with the theory of F-groups, 2-groups, and Bass-Serre theory of graphs of
groups.Comment: 39 pages, 2 figure
On the cohomology of stable map spaces
We describe an approach to calculating the cohomology rings of stable map
spaces. The method we use is due to Akildiz-Carrell and employs a C^*-action
and a vector field which is equivariant with respect to this C^*-action. We
give an explicit description of the big Bialynicky-Birula cell of the
C^*-action on Mbar_00(P^n,d) as a vector bundle on Mbar_0d. This is used to
calculate explicitly the cohomology ring of Mbar_00(P^n,d) in the cases d=2 and
d=3. Of particular interest is the case as n approaches infinity.Comment: 63 page
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