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121.
在文[1]基础上,提出一种仅知道派生线性系统零实部特征值时求解非线性系统非半单分叉NormalForm的方法.通过适当的分类,将要求解的线性代数方程组分为若干相互独立的方程组.将所求系数向量按字典序列排列后,各独立方程组的系数矩阵是上三角矩阵.在非共振情形,各系数向量可按反字典序列递推求出.在共振情形,根据文中的二个定理,巧妙地由一简单的常数矩阵的最大秩子矩阵,定位其系数矩阵的满秩子矩阵,解决了这类方程组的降维简化.通过消元法,把简化后的方程化成类似于半单分叉NormalForm求解过程中方程的形式,其解法也类似.该方法非常易于在计算机代数软件平台上程序化. 相似文献
122.
In this paper, we introduce a one-form associated to a Lagrangian immersion from Riemann surface into the complex hyperquadric . It is proved that is minimal if and only if is vanishing and is H-minimal if and only if is holomorphic. As an application, a family of -equivariant minimal Lagrangian tori in are obtained. 相似文献
123.
The rank of a graph is defined to be the rank of its adjacency matrix. A graph is called reduced if it has no isolated vertices and no two vertices with the same set of neighbors. We determine the maximum order of reduced triangle‐free graphs with a given rank and characterize all such graphs achieving the maximum order. 相似文献
124.
We examine in this paper some properties of Morita and Prüfer hulls of FCP and FIP extensions of rings. Dichotomy phenomena appear in the case of a quasi-local base ring. In the general case, we define relative supports that allow us to introduce the concept of direct factorization of an extension and to characterize these hulls. 相似文献
125.
Paolo Zanardo 《代数通讯》2015,43(1):158-173
Let R be a commutative ring and A be an R-module. The Mal'cev rank μ(A) of A is the sup of genN, where N ranges over the finitely generated submodules of A, and genN is the minimum number of generators of N. We prove that μ is both sub-additive and pre-additive as an invariant of Mod(R). Our main goal is to investigate μ for modules over pseudo-valuation domains. Specifically, we establish which pseudo-valuation domains R satisfy the property that an R-module of finite Mal'cev rank must be finitely generated. We split the class 𝒞 of pseudo-valuation domains as a union 𝒞 = 𝒞1 ∪ 𝒞2 ∪ 𝒞3 ∪ 𝒞4 of suitably defined subclasses, and prove that the property holds if and only if R ∈ 𝒞3 ∪ 𝒞4. In that case we can describe the R-modules A where μ(A) < ∞. We also show that, for R ∈ 𝒞4, there exist indecomposable R-modules of arbitrarily large finite Mal'cev rank. 相似文献
126.
Moufang sets were introduced by Jacques Tits in order to understand isotropic linear algebraic groups of relative rank one, but the notion is more general. We describe a new class of Moufang sets, arising from so‐called mixed groups of type in characteristic 2, obtained as the fixed point set under a suitable involution. 相似文献
127.
The blow-up solutions of the Cauchy problem for the Davey-Stewartson system, which is a model equation in the theory of shallow water waves, are investigated. Firstly, the existence of the ground state for the system derives the best constant of a Gagliardo-Nirenberg type inequality and the variational character of the ground state. Secondly, the blow-up threshold of the Davey-Stewartson system is developed in R3. Thirdly, the mass concentration is established for all the blow-up solutions of the system in R2. Finally, the existence of the minimal blow-up solutions in R2 is constructed by using the pseudo-conformal invariance. The profile of the minimal blow-up solutions as t→T (blow-up time) is in detail investigated in terms of the ground state. 相似文献
128.
We study three different problems in the area of Toeplitz operators on the Segal-Bargmann space in Cn. Extending results obtained previously by the first author and Y.L. Lee, and by the second author, we first determine the commutant of a given Toeplitz operator with a radial symbol belonging to the class Sym>0(Cn) of symbols having certain growth at infinity. We then provide explicit examples of zero-products of non-trivial Toeplitz operators. These examples show the essential difference between Toeplitz operators on the Segal-Bargmann space and on the Bergman space over the unit ball. Finally, we discuss the “finite rank problem”. We show that there are no non-trivial rank one Toeplitz operators Tf for f∈Sym>0(Cn). In all these problems, the growth at infinity of the symbols plays a crucial role. 相似文献
129.
130.
Nicolas Bouffard 《Nonlinear Analysis: Theory, Methods & Applications》2011,74(17):5815-5832
A semi-topological semigroup is strongly left amenable if there is a compact left ideal group in the spectrum of its LUC-compactification. In this paper, we want to study those objects, and study some fixed point property related to non-expansive mapping and other similar kind of mapping. 相似文献