共查询到20条相似文献,搜索用时 15 毫秒
1.
A. Georgakopoulos 《Abhandlungen aus dem Mathematischen Seminar der Universit?t Hamburg》2006,76(1):235-245
We construct infinite planar graphs of arbitrarily large connectivity and girth, and study their separation properties. These
graphs have no thick end but continuum many thin ones. Every finite cycle separates them, but they corroborate Diestel’s conjecture
that everyk-connected locally finite graph contains a possibly infinite cycle — see [3] — whose deletion leaves it (k — 3)-connected. 相似文献
2.
Wilhelm Plesken 《Archiv der Mathematik》2009,92(1):44-56
The paper introduces a new polynomial to count the solutions of a system of polynomial equations and inequations over an algebraically
closed field of characteristic zero based on the triangular decomposition algorithm by J. M. Thomas of the nineteen-thirties.
In the special case of projective varieties examples indicate that it is a finer invariant than the Hilbert polynomial.
Received: 8 March 2008; Revised: 12 August 2008 相似文献
3.
Daniela La Mattina 《manuscripta mathematica》2007,123(2):185-203
Let G be the infinite dimensional Grassmann algebra over a field F of characteristic zero and UT
2 the algebra of 2 × 2 upper triangular matrices over F. The relevance of these algebras in PI-theory relies on the fact that they generate the only two varieties of almost polynomial
growth, i.e., they grow exponentially but any proper subvariety grows polynomially. In this paper we completely classify,
up to PI-equivalence, the associative algebras A such that A ∈ Var(G) or A ∈ Var(UT
2). 相似文献
4.
A Cayley-like representation theorem for distributive lattices is proved.
Support of the research of the first author by the Czech Government Research Project MSM 6198959214 is gratefully acknowledged. 相似文献
5.
Michel Destrade Ray W. Ogden Giuseppe Saccomandi 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2009,60(3):511-528
We study the propagation of small amplitude waves superimposed on a large static deformation in a nonlinear viscoelastic material
of differential type. We use bulk waves and surface waves to address the questions of dissipation and of material and geometric
stability. In particular, the analysis provides bounds on the constitutive parameters and on the predeformation that ensure
linearized stability in the neighbourhood of a large pre-stretch. This type of result is relevant to the imaging of biological
soft tissues using acoustical techniques, where pre-deformation is known to increase contrast and reduce de-correlation noise.
This work was supported by GNFM (Italy) and by an International Joint Project grant awarded jointly by the Royal Society of
London (UK) and the CNRS (France). 相似文献
6.
Alberto Damiano 《Advances in Applied Clifford Algebras》2007,17(3):343-355
This paper is a short report on the generalization of some results of our previous paper [12] to the case of spin j/2 Dirac operators in real dimension three for arbitrary odd integer j. We use an explicit formula for the local expression of such operators to study their algebraic properties, construct the
compatibility conditions of the overdetermined system associated to the operator in several spatial variables, and we prove
that its associated algebraic complex, dual do the BGG sequence coming from representation theory, has substantially the same
pattern as the Cauchy-Fueter complex.
The author is a member of the Eduard Čech Center and his research is supported by the relative grants. 相似文献
7.
Hidetoshi Maeda 《Archiv der Mathematik》2007,88(5):419-424
Let
be an ample vector bundle of rank n – 1 on a smooth complex projective variety X of dimension n≥ 3 such that X is a
-bundle over
and that
for any fiber F of the bundle projection
. The pairs
with
= 2 are classified, where
is the curve genus of
. This allows us to improve some previous results.
Received: 13 June 2006 相似文献
8.
In this note we prove a generalization of the flat extension theorem of Curto and Fialkow (Memoirs of the American Mathematical
Society, vol. 119. American Mathematical Society, Providence, 1996) for truncated moment matrices. It applies to moment matrices
indexed by an arbitrary set of monomials and its border, assuming that this set is connected to 1. When formulated in a basis-free
setting, this gives an equivalent result for truncated Hankel operators.
相似文献
9.
Keiji Oguiso 《Mathematische Annalen》2009,344(4):929-937
We shall show that the Picard number of the generic fiber of an abelian fibered hyperkähler manifold over the projective space is always one. We then give a few applications for the Mordell-Weil group. In particular, by deforming O’Grady’s 10-dimensional manifold, we construct an abelian fibered hyperkähler manifold of Mordell-Weil rank 20, which is the maximum possible among all known ones. 相似文献
10.
Gábor Czédli 《Algebra Universalis》2009,60(2):217-230
Let L be a bounded lattice. If for each a1 < b1 ∈ L and a2 < b2 ∈ L there is a lattice embedding ψ: [a1, b1] → [a2, b2] with ψ(a1) = a2 and ψ(b1) = b2, then we say that L is a quasifractal. If ψ can always be chosen to be an isomorphism or, equivalently, if L is isomorphic to each of its nontrivial intervals, then L will be called a fractal lattice. For a ring R with 1 let denote the lattice variety generated by the submodule lattices of R-modules. Varieties of this kind are completely described in [16]. The prime field of characteristic p will be denoted by Fp.
Let be a lattice variety generated by a nondistributive modular quasifractal. The main theorem says that is neither too small nor too large in the following sense: there is a unique , a prime number or zero, such that and for any n ≥ 3 and any nontrivial (normalized von Neumann) n-frame of any lattice in , is of characteristic p. We do not know if in general; however we point out that, for any ring R with 1, implies . It will not be hard to show that is Arguesian.
The main theorem does have a content, for it has been shown in [2] that each of the is generated by a single fractal lattice Lp; moreover we can stipulate either that Lp is a continuous geometry or that Lp is countable.
The proof of the main theorem is based on the following result of the present paper: if is a nontrivial m-frame and is an n-frame of a modular lattice L with m, n ≥ 3 such that and , then these two frames have the same characteristic and, in addition, they determine a nontrivial mn-frame of the same characteristic in a canonical way, which we call the product frame.
Presented by E. T. Schmidt. 相似文献
11.
Universal Laurent series where the universal approximation is valid on the boundary of the multiple connected open Ω appears
for the first time in [2]. We show that it is possible to demand universal approximation only to a part of the boundary while
on the remaining part the universal function can be smooth.
Received: 29 May 2007 相似文献
12.
Milan Paštéka 《Mediterranean Journal of Mathematics》2009,6(1):125-134
In the first part some conditions under which a permutation preserves Buck’s measure density, are derived. In the second part
is constructed a countable system of permutations which has the ergodic property on the system of Buck’s measurable sets.
Received: March 27, 2007., Accepted: August 25, 2008. 相似文献
13.
Chunjie Wang 《Integral Equations and Operator Theory》2008,61(3):423-432
Let and m be a positive integer. We obtain a condition under which . As an application we get an upper bound on Korenblum’s constant . We also give another proof of a well-known result concerning the domination problem in the Bergman space.
This work was supported by NNSF of China No. 10601025 and the Natural Science Foundation of Hebei Province of China (No. 07M001). 相似文献
14.
An absorption law is an identity of the form p = x. The ternary function x+y+z (ring addition) in Boolean algebras satisfies three absorption laws in two variables. If a term satisfies these three identities
in a variety, it is called a minority term for that variety. We construct a minority term p for orthomodular lattices such the identity defines Boolean algebras modulo orthomodular lattices. (The dual of p is denoted by .) Consequently, having a unique minority term function characterizes Boolean algebras among orthomodular lattices. Our main
result generalizes this example to arbitrary arity and arbitrary consistent sets of 2-variable absorption laws.
Presented by J. Berman. 相似文献
15.
Lei Zhu 《manuscripta mathematica》2009,129(1):99-126
For a canonical threefold of general type, we know that the pluri–canonical map is stably birational for a sufficiently large n. This paper aims to find the lower bound of n for such kind of threefolds with χ = 1. To prove our main result, we will estimate the lower bound of plurigenus.
L. Zhu is supported by Fudan Graduate Students’ Innovation Projects (EYH5928004). 相似文献
16.
In this paper we study K3 surfaces with a non-symplectic automorphism of order 3. In particular, we classify the topological
structure of the fixed locus of such automorphisms and we show that it determines the action on cohomology. This allows us
to describe the structure of the moduli space and to show that it has three irreducible components. 相似文献
17.
We show that the orbifold Chow ring of a root stack over a well-formed weighted projective space can be naturally seen as
the Jacobian algebra of a function on a singular variety. 相似文献
18.
P. CsöRGő A. Drápal 《Abhandlungen aus dem Mathematischen Seminar der Universit?t Hamburg》2006,76(1):17-34
A loopQ is said to be left conjugacy closed (LCC) if the left translations form a set of permutations that is closed under conjugation. This papers investigates those LCC loops where the group generated by left translations is normal in the group generated by both left and right translations. 相似文献
19.
Alzati A. Bertolini M. Besana G. 《Abhandlungen aus dem Mathematischen Seminar der Universit?t Hamburg》2004,74(1):57-75
Smooth, complex, ruled surfaces embedded in ℙ5 as linearly normal scrolls, such that they are contained in a quadric cone, are considered. Rational scrolls and some elliptic
scrolls are shown to be the only ones contained in cones of rank 5. Results on scrolls contained in cones of lower ranks are
also obtained. 相似文献
20.
Roland Donninger 《Journal of Evolution Equations》2009,9(3):511-523
We consider the radial wave equation in similarity coordinates within the semigroup formalism. It is known that the generator
of the semigroup exhibits a continuum of eigenvalues and embedded in this continuum there exists a discrete set of eigenvalues
with analytic eigenfunctions. Our results show that, for sufficiently regular data, the long-time behaviour of the solution
is governed by the analytic eigenfunctions. The same techniques are applied to the linear stability problem for the fundamental
self-similar solution χ
T
of the wave equation with a focusing power nonlinearity. Analogous to the free wave equation, we show that the long-time
behaviour (in similarity coordinates) of linear perturbations around χ
T
is governed by analytic mode solutions. In particular, this yields a rigorous proof for the linear stability of χ
T
with the sharp decay rate for the perturbations.
相似文献