75,572 research outputs found
Hamiltonian circle actions with minimal isolated fixed points
Let the circle act in a Hamiltonian fashion on a compact symplectic manifold
of dimension . Then the -action has at least fixed
points. We study the case when the fixed point set consists of precisely
isolated points. We show certain equivalence on the first Chern class of
and some particular weight of the -action at some fixed point. We show
that the particular weight can completely determine the integral cohomology
ring of , the total Chern class of , and the sets of weights of the
-action at all the fixed points. We will see that all these data are
isomorphic to those of known examples, \CP^n, or \Gt_2(\R^{n+2}) with
odd, equipped with standard circle actions.Comment: title is slightly changed. Some contents are change
Twisted Topological Graph Algebras
We define the notion of a twisted topological graph algebra associated to a
topological graph and a -cocycle on its edge set. We prove a stronger
version of a Vasselli's result. We expand Katsura's results to study twisted
topological graph algebras. We prove a version of the Cuntz-Krieger uniqueness
theorem, describe the gauge-invariant ideal structure. We find that a twisted
topological graph algebra is simple if and only if the corresponding untwisted
one is simple.Comment: 27 page
The fundamental groups of contact toric manifolds
Let be a connected compact contact toric manifold. Most of such manifolds
are of Reeb type. We show that if is of Reeb type, then is
finite cyclic, and we describe how to obtain the order of from the
moment map image.Comment: This version is the published on
- β¦