7,029 research outputs found

    Teacher-stress and present day grading practices

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    Includes bibliographical references

    Uniformization of Deligne-Mumford curves

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    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 P(n1,n2,...,nr)\mathcal{P}(n_1,n_2,...,n_r). 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

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    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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