1,558 research outputs found
A note on the growth factor in Gaussian elimination for generalized Higham matrices
The Higham matrix is a complex symmetric matrix A=B+iC, where both B and C
are real, symmetric and positive definite and is the
imaginary unit. For any Higham matrix A, Ikramov et al. showed that the growth
factor in Gaussian elimination is less than 3. In this paper, based on the
previous results, a new bound of the growth factor is obtained by using the
maximum of the condition numbers of matrixes B and C for the generalized Higham
matrix A, which strengthens this bound to 2 and proves the Higham's conjecture.Comment: 8 pages, 2 figures; Submitted to MOC on Dec. 22 201
Beyond the 2nd Fermi Pulsar Catalog
Over thirteen times more gamma-ray pulsars have now been studied with the
Large Area Telescope on NASA's Fermi satellite than the ten seen with the
Compton Gamma-Ray Observatory in the nineteen-nineties. The large sample is
diverse, allowing better understanding both of the pulsars themselves and of
their roles in various cosmic processes. Here we explore the prospects for even
more gamma-ray pulsars as Fermi enters the 2nd half of its nominal ten-year
mission. New pulsars will naturally tend to be fainter than the first ones
discovered. Some of them will have unusual characteristics compared to the
current population, which may help discriminate between models. We illustrate a
vision of the future with a sample of six pulsars discovered after the 2nd
Fermi Pulsar Catalog was written.Comment: 6 pages, to appear in the proceedings of "The Fast and the Furious:
Energetic Phenomena in Isolated Neutron Stars, Pulsar Wind Nebulae and
Supernova Remnants",ESAC, Madrid, Spain, 22 - 24 May 2013
http://xmm.esac.esa.int/external/xmm_science/workshops/2013_science/, to be
published as a regular issue of the Astronomische Nachrichten / Astronomical
Notes (AN
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