575 research outputs found
Finite groups having the same prime graph as the group Aut(J2)
Finite groups having the same prime graph as the group Aut(J 2) are described. This solves the problem posed by B. Khosravi. © 2013 Pleiades Publishing, Ltd
The complete reducibility of some GF(2)A7-modules
It is proved that, if G is a finite group with a nontrivial normal 2-subgroup Q such that G/Q ∼= A 7 and an element of order 5 from G acts freely on Q, then the extension G over Q is splittable, Q is an elementary abelian group, and Q is the direct product of minimal normal subgroups of G each of which is isomorphic, as a G/Q-module, to one of the two 4-dimensional irreducible GF(2)A7-modules that are conjugate with respect to an outer automorphism of the group A7. © 2013 Pleiades Publishing, Ltd
The inf-sup constant for the divergence on corner domains
The inf-sup constant for the divergence, or LBB constant, is related to the
Cosserat spectrum. It has been known for a long time that on non-smooth domains
the Cosserat operator has a non-trivial essential spectrum, which can be used
to bound the LBB constant from above. We prove that the essential spectrum on a
plane polygon consists of an interval related to the corner angles and that on
three-dimensional domains with edges, the essential spectrum contains such an
interval. We obtain some numerical evidence for the extent of the essential
spectrum on domains with axisymmetric conical points by computing the roots of
explicitly given holomorphic functions related to the corner Mellin symbol.
Using finite element discretizations of the Stokes problem, we present
numerical results pertaining to the question of the existence of eigenvalues
below the essential spectrum on rectangles and cuboids
Function Spaces on Singular Manifolds
It is shown that most of the well-known basic results for Sobolev-Slobodeckii
and Bessel potential spaces, known to hold on bounded smooth domains in
, continue to be valid on a wide class of Riemannian manifolds
with singularities and boundary, provided suitable weights, which reflect the
nature of the singularities, are introduced. These results are of importance
for the study of partial differential equations on piece-wise smooth domains.Comment: 37 pages, 1 figure, final version, augmented by additional
references; to appear in Math. Nachrichte
Precanonical quantization of Yang-Mills fields and the functional Schroedinger representation
Precanonical quantization of pure Yang-Mills fields, which is based on the
covariant De Donder-Weyl (DW) Hamiltonian formalism, and its connection with
the functional Schrodinger representation in the temporal gauge are discussed.
The YM mass gap problem is related to a finite dimensional spectral problem for
a generalized Clifford-valued magnetic Schr\"odinger operator in the space of
gauge potentials which represents the DW Hamiltonian operator.Comment: LaTeX2e, 11pages. v2: 13 pages, minor changes, references added,
sect. 5 extended, to appear in Rep. Math. Phy
An efficient direct solver for a class of mixed finite element problems
In this paper we present an efficient, accurate and parallelizable direct method for the solution of the (indefinite) linear algebraic systems that arise in the solution of fourth-order partial differential equations (PDEs) using mixed finite element approximations. The method is intended particularly for use when multiple right-hand sides occur, and when high accuracy is required in these solutions.
The algorithm is described in some detail and its performance is illustrated through the numerical solution of a biharmonic eigenvalue problem where the smallest eigenpair is approximated using inverse iteration after discretization via the Ciarlet–Raviart mixed finite element method
Consideration of soil strata heterogeneity influence on differential foundation settlements of overpasses for high-speed railways
The implementation of projects for the construction of high-speed railways actualizes the search of effective approaches to accounting the influence of soil strata heterogeneity along the course of the track on differential foundation settlements of overpasses. Russian special technical conditions prescribe sufficiently stringent regulation limits of absolute values of overpasses' foundation soil settlements (20 mm for ballastless track) and angles of break in profile (the differential foundation soil settlement), which should not exceed 1 ‰ for ballastless track. These requirements make it necessary to develop the calculation method, which is based on the criterion of deformation. To ensure compliance of design solutions to the specified regulations it is appropriate to use the method of the predefined equated soil settlements for design of shallow foundations of overpasses for high-speed railways. Several features of application of this method are presented in this article
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