Weakly strongly singular integral operators on anisotropic Hardy spaces and their dual operators

Let A be an expansive dilation. We define weakly strongly singular integral kernels and study the action of the operators induced by these kernels on anisotropic Hardy spaces associated with A.     

GP-V'-环的von Neumann正则性

本文研究了GP-V'-环的von Neumann正则性问题.利用GW-理想和W-理想的性质及方法,得到了 GP-V'-环是(强)正则环的一些条件,推广了文献[3,6]中的相关结果.     

Transformation d'halphen

We give a modern version of the following result of Halphen: “degrees and classes of successive evolutes of a plane algebraic curve form two arithmetic progressions of the same ratio after a sufficient number of iterations”. The iteration of this transform provides a desingularisationprocess (branch by branch) of plane curves, different to the Nash transform and the Noether process. To prove these two points,we introduce systematically Puiseux's exponents, semi-groups of exponents and use elimination and duality formulae.     

Multiple solutions for a semilinear elliptic system in

In this paper, we study the following semilinear elliptic system where N > 2, f(x,t) and g(x,t) are continuous functions and satisfy additional conditions. By using critical point theory of strongly indefinite functionals, we obtain a positive ground state solution and infinitely many geometrically distinct solutions when f(x,t) and g(x,t) are periodic in X and odd in t. Copyright © 2013 John Wiley & Sons, Ltd.     

First-principles calculations of electronic and magnetic properties of CeN： The LDA ＋ U method

Electronic and magnetic properties of CeN are investigated using first-principles calculations based on density func- tional theory （DFT） with the LDA ＋ U method. Our results show that CeN is a half-metal. The majority-spin electron band structure has metallic intersections, whereas the minority-spin electron band structure has a semiconducting gap straddling the Fermi level. A small indirect energy gap occurs between X and W. The calculated magnetic moment is 0.99 μb per unit cell.     

Asymptotic enumeration of strongly connected digraphs by vertices and edges

We derive an asymptotic formula for the number of strongly connected digraphs with n vertices and m arcs (directed edges), valid for m ‐ n →∞ as n →∞ provided m = O(nlog n). This fills the gap between Wright's results which apply to m = n + O (1) , and the long‐known threshold for m, above which a random digraph with n vertices and m arcs is likely to be strongly connected. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 2013     

Finiteness Results in Triangle‐Free Quasi‐Symmetric Designs

Triangle‐free quasi‐symmetric 2‐ designs with intersection numbers ; and are investigated. Possibility of triangle‐free quasi‐symmetric designs with or is ruled out. It is also shown that, for a fixed x and a fixed ratio , there are only finitely many triangle‐free quasi‐symmetric designs. © 2012 Wiley Periodicals, Inc. J Combin Designs 00: 1‐6, 2012     

Strongly regular Cayley graphs and rationality of relative Gauss sums

In this note, we give a construction of strongly regular Cayley graphs. The presented construction is based on choosing cyclotomic classes in finite fields, and our results generalize ten of the eleven sporadic examples of cyclotomic strongly regular graphs given by Schmidt and White [B. Schmidt, C. White, All two-weight irreducible cyclic codes, Finite Fields Appl. 8 (2002), 321–367] into infinite families. These infinite families of strongly regular graphs have new parameters. The main tools that we employed are relative Gauss sums instead of explicit evaluations of Gauss sums.     

Quantum Impurity Models with Coupled Cluster Method

We investigate the ground-state properties of the Anderson single impurity model （finite Coulomb impurity repulsion） with the Coupled Cluster Method. We consider different CCM reference states and approximation schemes and make comparison with exact Green＇s function results for the non-interacting model and with Brillouin-Wigner perturbation theory for the full interacting model. Our results show that coupled cluster techniques are well suited to quantum impurity problems.