7,649 research outputs found
On the leading coefficient of polynomials orthogonal over domains with corners
Let be the interior domain of a piecewise analytic Jordan curve without
cusps. Let be the sequence of polynomials that are
orthonormal over with respect to the area measure, with each having
leading coefficient . N. Stylianopoulos has recently proven that
the asymptotic behavior of as is given by where
as and is the reciprocal of the
logarithmic capacity of the boundary . In this paper, we prove that
the estimate for the error term is, in general, best
possible, by exhibiting an example for which The proof makes use of the Faber
polynomials, about which a conjecture is formulated.Comment: 7 page
The Coexistence of Classical Bulges, Pseudobulges, and Supermassive Black Holes
Some S0 and early-type spiral galaxies possess "composite bulges"; in these
galaxies, the photometric bulge -- the central stellar light in excess of the
disk light -- is composed of both a "(disky) pseudobulge", with a flattened,
disklike morphology and relatively cool stellar kinematics, and a rounder,
kinematically hot "classical bulge" embedded within. I speculate that
supermassive black holes (SMBH) in such galaxies may correlate with the
classical-bulge component only, and not with the pseudobulge component;
preliminary comparisons with SMBH masses appear to support this hypothesis.Comment: LaTeX, 4 pages, 2 PDF figures. To appear in the proceedings of "The
Monster's Fiery Breath: Feedback in Galaxies, Groups, and Clusters", eds.
Sebastian Heinz and Eric Wilcots (AIP conference series
Can D-Branes Wrap Nonrepresentable Cycles?
Sometimes a homology cycle of a nonsingular compactification manifold cannot
be represented by a nonsingular submanifold. We want to know whether such
nonrepresentable cycles can be wrapped by D-branes. A brane wrapping a
representable cycle carries a K-theory charge if and only if its Freed-Witten
anomaly vanishes. However some K-theory charges are only carried by branes that
wrap nonrepresentable cycles. We provide two examples of Freed-Witten
anomaly-free D6-branes wrapping nonrepresentable cycles in the presence of a
trivial NS 3-form flux. The first occurs in type IIA string theory compactified
on the Sp(2) group manifold and the second in IIA on a product of lens spaces.
We find that the first D6-brane carries a K-theory charge while the second does
not.Comment: 11 pages, no figure
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