18,133 research outputs found
Hermitian codes from higher degree places
Matthews and Michel investigated the minimum distances in certain
algebraic-geometry codes arising from a higher degree place . In terms of
the Weierstrass gap sequence at , they proved a bound that gives an
improvement on the designed minimum distance. In this paper, we consider those
of such codes which are constructed from the Hermitian function field. We
determine the Weierstrass gap sequence where is a degree 3 place,
and compute the Matthews and Michel bound with the corresponding improvement.
We show more improvements using a different approach based on geometry. We also
compare our results with the true values of the minimum distances of Hermitian
1-point codes, as well as with estimates due Xing and Chen
A two-component model for fitting light-curves of core-collapse supernovae
We present an improved version of a light curve model, which is able to
estimate the physical properties of different types of core-collapse supernovae
having double-peaked light curves, in a quick and efficient way. The model is
based on a two-component configuration consisting of a dense, inner region and
an extended, low-mass envelope. Using this configuration, we estimate the
initial parameters of the progenitor via fitting the shape of the
quasi-bolometric light curves of 10 SNe, including Type IIP and IIb events,
with model light curves. In each case we compare the fitting results with
available hydrodynamic calculations, and also match the derived expansion
velocities with the observed ones. Furthermore, we also compare our
calculations with hydrodynamic models derived by the SNEC code, and examine the
uncertainties of the estimated physical parameters caused by the assumption of
constant opacity and the inaccurate knowledge of the moment of explosion
Light dual multinets of order six in the projective plane
The aim of this paper is twofold: First we classify all abstract light dual
multinets of order which have a unique line of length at least two. Then we
classify the weak projective embeddings of these objects in projective planes
over fields of characteristic zero. For the latter we present a computational
algebraic method for the study of weak projective embeddings of finite
point-line incidence structures
Group-labeled light dual multinets in the projective plane (with Appendix)
In this paper we investigate light dual multinets labeled by a finite group
in the projective plane defined over a field .
We present two classes of new examples. Moreover, under some conditions on the
characteristic , we classify group-labeled light dual multinets
with lines of length least
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