2,216 research outputs found
Generic coverings of plane with A-D-E-singularities
We generalize results of the paper math.AG/9803144, in which Chisini's
conjecture on the unique reconstruction of f by the curve B is investigated.
For this fibre products of generic coverings are studied. The main inequality
bounding the degree of a covering in the case of existence of two nonequivalent
coverings with the branch curve B is obtained. This inequality is used for the
proof of the Chisini conjecture for m-canonical coverings of surfaces of
general type for .Comment: 43 pages, 20 figures; to appear in Izvestiya Mat
On braid monodromy factorizations
We introduce and develop a language of semigroups over the braid groups for a
study of braid monodromy factorizations (bmf's) of plane algebraic curves and
other related objects. As an application we give a new proof of Orevkov's
theorem on realization of a bmf over a disc by algebraic curves and show that
the complexity of such a realization can not be bounded in terms of the types
of the factors of the bmf. Besides, we prove that the type of a bmf is
distinguishing Hurwitz curves with singularities of inseparable types up to
-isotopy and -holomorphic cuspidal curves in \C P^2 up to symplectic
isotopy.Comment: 52 pages, AMS-Te
Regular homotopy of Hurwitz curves
We prove that any two irreducible cuspidal Hurwitz curves and (or
more generally, curves with A-type singularities) in the Hirzebruch surface
with coinciding homology classes and sets of singularities are regular
homotopic; and symplectically regular homotopic if and are
symplectic with respect to a compatible symplectic form.Comment: 26 page
Models and phenomenology
It is evident that models of the knee should match the observational
phenomenology. In this talk I discuss a few aspects of phenomenology, which are
important not only for the understanding of the knee origin, but also for the
general problem of the origin of cosmic rays. Among them are the shape of the
energy spectrum, its irregularity, the sharpness of the knee and its fine
structure. The classification of models is given and some examples of the most
recent models are discussed. The most probable conclusion deduced from this
examination is that the knee has an astrophysical origin and the so called
'source' models of the knee are most likely among them.Comment: 13 pages, 4 figures, overview talk at 19th European Cosmic Ray
Symposium, Firenze, Italy, 30.08-4.09.2004 (to be published in the
Int.J.Mod.Phys.A
On the upper limit of antinuclei content in cosmic rays
Upper limit of antinuclei content in cosmic ray
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