2,136 research outputs found
Braid Monodromy Factorization and Diffeomorphism Types
In this manuscript we prove that if two cuspidal plane curves have equivalent
braid monodromy factorizations, then they are smoothly isotopic in the plane.
As a consequence of this and the Chisini conjecture, we obtain that if two
discriminant curves (or branch curves in other terminology) of generic
projections (to the plane) of surfaces of general type imbedded in a projective
space by means of a multiple canonical class have equivalent braid monodromy
factorizations, then the surfaces are diffeomorphic (if we consider them as
real 4-folds).Comment: 2 files: TEX file of text and file of figures (gzipped
On Symplectic Coverings of the Projective Plane
We prove that a resolution of singularities of any finite covering of the
projective plane branched along a Hurwitz curve and, maybe, along a
line "at infinity" can be embedded as a symplectic submanifold into some
projective algebraic manifold equipped with an integer K\"{a}hler symplectic
form (assuming that if has negative nodes, then the covering is
non-singular over them). For cyclic coverings we can realize this embeddings
into a rational algebraic 3--fold. Properties of the Alexander polynomial of
are investigated and applied to the calculation of the first Betti
number of a resolution of singularities of
-sheeted cyclic coverings of branched along
and, maybe, along a line "at infinity". We prove that is even
if is an irreducible Hurwitz curve but, in contrast to the algebraic
case, that it can take any non-negative value in the case when
consists of several irreducible components.Comment: 42 page
Dynamics of abelian subgroups of GL(n, C): a structure's Theorem
In this paper, we characterize the dynamic of every abelian subgroups
of GL(, ), or
. We show that there exists a -invariant, dense open
set in saturated by minimal orbits with a union of at most -invariant vectorial subspaces of
of dimension or on . As a consequence,
has height at most and in particular it admits a minimal set
in .Comment: 16 page
Thermodynamic modeling and analysis of the structure of a heat-resistant alloy of the Fe-Cr-Ni system
There has been carried out thermodynamic modeling of phase transformations of the Fe-Cr Ni alloy alloyed with titanium and niobium in order to predict the phase composition and to substantiate the concentration of alloying elements of the experimental alloy for parts of metallurgical equipment. The results of microstructural analysis and phase composition of an experimental heat-resistant alloy are presented
Thermodynamic modeling and analysis of the structure of a heat-resistant alloy of the Fe-Cr-Ni system
There has been carried out thermodynamic modeling of phase transformations of the Fe-Cr Ni alloy alloyed with titanium and niobium in order to predict the phase composition and to substantiate the concentration of alloying elements of the experimental alloy for parts of metallurgical equipment. The results of microstructural analysis and phase composition of an experimental heat-resistant alloy are presented
Multilevel Parallelization: Grid Methods for Solving Direct and Inverse Problems
In this paper we present grid methods which we have developed for solving direct and inverse problems, and their realization with different levels of optimization. We have focused on solving systems of hyperbolic equations using finite difference and finite volume numerical methods on multicore architectures. Several levels of parallelism have been applied: geometric decomposition of the calculative domain, workload distribution over threads within OpenMP directives, and vectorization. The run-time efficiency of these methods has been investigated. These developments have been tested using the astrophysics code AstroPhi on a hybrid cluster Polytechnic RSC PetaStream (consisting of Intel Xeon Phi accelerators) and a geophysics (seismic wave) code on an Intel Core i7-3930K multicore processor. We present the results of the calculations and study MPI run-time energy efficiency
The Geometry and Moduli of K3 Surfaces
These notes will give an introduction to the theory of K3 surfaces. We begin
with some general results on K3 surfaces, including the construction of their
moduli space and some of its properties. We then move on to focus on the theory
of polarized K3 surfaces, studying their moduli, degenerations and the
compactification problem. This theory is then further enhanced to a discussion
of lattice polarized K3 surfaces, which provide a rich source of explicit
examples, including a large class of lattice polarizations coming from elliptic
fibrations. Finally, we conclude by discussing the ample and Kahler cones of K3
surfaces, and give some of their applications.Comment: 34 pages, 2 figures. (R. Laza, M. Schutt and N. Yui, eds.
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