Characterizations of PG(n − 1, q)\PG(k − 1, q) by Numerical and Polynomial Invariants

We show that the simple matroid PG(n − 1, q)\PG(k − 1, q), for n ≥ 4 and 1 ≤ k ≤ n − 2, is characterized by a variety of numerical and polynomial invariants. In particular, any matroid that has the same Tutte polynomial as PG(n − 1, q)\PG(k − 1, q) is isomorphic to PG(n − 1, q)\PG(k − 1, q).     

Caractérisation des codes auto-duaux binaires de type II à partir du code de Hamming étendu [8, 4, 4]

We show that any binary type II code can be built as a Cortex code where the basis code is the [8,4,4] extended Hamming code. To cite this article: A. Otmani, C. R. Acad. Sci. Paris, Ser. I 336 (2003).     

A non-variational approach to the construction of new ‘higher-order’ conservation laws of the family of nonlinear equations α(ut + 3uux) + β(utxx + 2uxuxx + uuxxx) − γuxxx = 0

In this paper, we study and classify the conservation laws of the combined nonlinear KdV, Camassa–Holm, Hunter–Saxton and the inviscid Burgers equation which arises in, inter alia, shallow water equations. It is shown that these can be obtained by variational methods but the main focus of the paper is the construction of the conservation laws as a consequence of the interplay between symmetry generators and ‘multipliers’, particularly, the higher-order ones.     

1 : 3-Resonance in a Hopf–Hopf bifurcation

We investigate the bifurcating solutions at a Hopf–Hopf interaction point with an internal 1 : 3 resonance. It turns out, that the transitions from single to mixed modes can be described by Duffing or Mathieu szenarios. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Developing interaction potential for H (2H) → Cu(1 1 1) interaction system: A numerical study

In this study, we have used London–Eyring–Polanyi–Sato (LEPS) functional form as an interaction potential energy function to simulate H (2H) → Cu(1 1 1) interaction system. The parameters of the LEPS function are determined in order to analyze reaction dynamics via molecular dynamics computer simulations of the Cu(1 1 1) surface and H/(2H) system. Nonlinear least-squares method is used to find the LEPS parameters. For this purpose, we use the energy points which were calculated by a density-functional theory method with the generalized gradient approximation including exchange-correlation energy for various configurations of one and two hydrogen atoms on the Cu(1 1 1) surface. After the fitting procedures, two different parameters sets are obtained that the calculated root-mean-square values are close to each other. Using these sets, contour plots of the potential energy surfaces are analyzed for H → Cu(1 1 1) and 2H → Cu(1 1 1) interactions systems. In addition, sticking, penetration, and scattering sites on the surface are analyzed by using these sets.     

Combinatorial identities related to 2 × 2 submatrices of recursive matrices

Recursive matrices are ubiquitous in combinatorics, which have been extensively studied. We focus on the study of the sums of 2 × 2 minors of certain recursive matrices, the alternating sums of their 2 × 2 minors, and the sums of their 2 × 2 permanents. We obtain some combinatorial identities related to these sums, which generalized the work of Sun and Ma (2014) [23,24]. With the help of the computer algebra package HolonomicFunctions, we further get some new identities involving Narayana polynomials.     

On left (θ, ϕ)-derivations in BCI-algebras

The notion of (regular) left (θ, ϕ)-derivations of a BCI-algebra is introduced, some useful examples are discussed, and related properties are investigated. Conditions for a left (θ, ϕ)-derivation to be regular are provided. The concepts of a d_(θ,ϕ)-invariant left (θ, ϕ)-derivation and θ-ideal are introduced, and their relations are discussed. Furthermore, some more interesting results are established.     

Analytic integrability of the Bianchi class A cosmological models with 0 ⩽ k < 1

Many works study the integrability of the Bianchi class A cosmologies with k = 1, where k is the ratio between the pressure and the energy density of the matter. Here we characterize the analytic integrability of the Bianchi class A cosmological models when 0 ⩽ k < 1. We conclude that Bianchi types VI₀, VII₀, VIII and IX can exhibit chaos whereas Bianchi type I is not chaotic and Bianchi type II is at most partially chaotic.     

黑洞的量子统计熵

避开求解各种粒子波动方程的困难,直接应用量子统计的方法,计算各种坐标描述的黑洞背景下玻色场与费米场的配分函数,得到黑洞熵的积分表达式.然后应用改进的brick wall方法 膜模型,计算黑洞的统计熵.在所得结果中取适当的参数,可得到黑洞熵与视界面积成正比的关系,不存在原brick wall方法中的舍去项与对数发散项.整个计算过程,物理图像清楚,计算简单,为研究各种坐标下黑洞熵提供了一条简捷的新途经.     

一类乘子收敛级数空间

仅仅依靠序列空间λ的内蕴性质, 作者给出了λ -乘数收敛级数空间X(λ)上的一个局部凸拓扑T_Β, 并证明了(X(λ), T_Β)是AK -空间, 具有序列完备性和Banach-Steinhaus性质. 特别是作者给出了此空间上的一个改进的Orlicz-Pettis定理.     

Two 3 × 3 discrete matrix spectral problems and associated Liouville integrable lattice soliton equations

Two 3 × 3 discrete matrix spectral problems are introduced and the corresponding lattice soliton equations are derived. By means of the discrete trace identity the Hamiltonian structures of the resulting equations are constructed. Liouville integrability of the discrete Hamiltonian systems is proved.     

Finsler流形上的Laplace算子

该文对Finsler流形上的微分式定义了整体内积，进而引入δ算子和Laplace算子。该文还给出了δ算子的局部坐标表达式并且证明了Laplace算子可以看成是Riemann流形上Laplace算子在Finsler流形上的扩张。     

Felix Hausdorff: Gesammelte Werke. Band VI. Geometrie,Raum und Zahl,hg. von M. Epple (Berlin: Springer, 2021). ISBN 978-3-540-77838-7. XX 540 Seiten. 89,99 €

Mathematische Semesterberichte -     

p -级数域重排特征系统的(C, α)}和

令G_p 为p级数域.在文献[9]中, G.Gát 和 K.Nagy 已经证明p级数域的重排特征系统的(C,1)极大算子是强 (q, q)型(1 α_n f 几乎处处收敛于f.     

On the natural solution of an impulsive fractional differential equation of order q ∈ (1, 2)

This paper is motivated from some recent papers treating the impulsive Cauchy problems for some differential equations with fractional order q ∈ (1, 2). A better definition of solution for impulsive fractional differential equation is given. We build up an effective way to find natural solution for such problems. Then sufficient conditions for existence of the solutions are established by applying fixed point methods. Four examples are given to illustrate the results.     

Three-dimensional modulation of electron-acoustic waves: 3 + 1 Davey–Stewartson system

In this paper we consider the three-dimensional modulation of an electron-acoustic wave by means of a multiple-scale perturbation method. We find that the governing equation for the amplitude that describes the asymptotic properties of the wave is a Davey–Stewartson system in three-space variables. We use the system to study the linear stability of the modulation wave and we compare our results with preceding studies by Kourakis and Shukla (2004) [8] on the oblique modulation problem based on a non-linear Schrödinger equation.     

Dirichlet空间上的循环复合算子

该文主要证明了在Dirichlet空间上由复合算子{C\-φ:φ∈Aut(D)}生成的代数为循环算子代数;同时对任意的解析映射φ:D→D,C\-φ都不可能为超循环算子给出了证明.