Gröbner-Shirshov Bases of Irreducible Modules of the Quantum Group of Type G2

First, the authors give a Grbner-Shirshov basis of the finite-dimensional irreducible module Vq(λ) of the Drinfeld-Jimbo quantum group U_q(G_2) by using the double free module method and the known Grbner-Shirshov basis of U_q(G_2). Then, by specializing a suitable version of U_q(G_2) at q = 1, they get a Grbner-Shirshov basis of the universal enveloping algebra U(G_2) of the simple Lie algebra of type G_2 and the finite-dimensional irreducible U(G_2)-module V(λ).     

Dunkl’s theory and best approximation by entire functions of exponential type in L 2-metric with power weight

In this paper, we study the sharp Jackson inequality for the best approximation of f ∈L2,κ(Rd) by a subspace E2κ(σ)(SE2κ(σ)), which is a subspace of entire functions of exponential type(spherical exponential type) at most σ. Here L2,κ(Rd) denotes the space of all d-variate functions f endowed with the L2-norm with the weight v2κ(x) =ξ∈R, which is defined by a positive+|(ξ, x)|κ(ξ)subsystem R+ of a finite root system RRdand a function κ(ξ) : R → R+ invariant under the reflection group G(R) generated by R. In the case G(R) = Zd2, we get some exact results. Moreover,the deviation of best approximation by the subspace E2κ(σ)(SE2κ(σ)) of some class of the smooth functions in the space L2,κ(Rd) is obtained.     

q-Deformation of W（2, 2） Lie Algebra Associated with Quantum Groups

The q-deformation of W (2, 2) Lie algebra is well defined based on a realization of this Lie algebra by using the famous bosonic and fermionic oscillators in physics. Furthermore, the quantum group structures on the q-deformation of W (2, 2) Lie algebra are completely determined. Finally, the 1-dimensional central extension of the q-deformed W (2, 2) Lie algebra is studied, which turns out to be coincided with the conventional W (2, 2) Lie algebra in the q → 1 limit.     

Beurling-Ahlfors扩张的伸张函数的估计

In this paper, we prove that the control function of the dilatation function of Beurling-Ahlfors extension is convex. Using the quasi-symmetric function ρ, we get a relatively sharp estimate of the dilatation function: D(x,y)≤17/32 (ρ(x, y) 1) (ρ(x y/2, y/2) ρ(x - y/2, y/2) 2) , which improves the results before. We also show that the above result is asymptotically precise.     

Zeros of the Jones Polynomial for Torus Knots and 2-bridge Knots

We study zeros of the Jones polynomial and their distributions for torus knots and 2-bridge knots. We prove that e(2m+1)πi/2and e(2m+1)πi/4(m is a positive integer)can not be the zeros of Jones polynomial for torus knots T p,q by the knowledge of the trigonometric function. We elicit the normal form of Jones polynomials of the 2-bridge knot C(-2, 2, · · ·,(-1)r2) by the recursive form and discuss the distribution of their zeros.     

二树的ABC指标

The atom-bond connectivity(ABC) index of a graph G, introduced by Estrada,Torres, Rodr′?guez and Gutman in 1998, is defined as the sum of the weights(1/di+1/dj-2/didj )~(1/2) of all edges vivj of G, where di denotes the degree of the vertex vi in G. In this paper, we give an upper bound of the ABC index of a two-tree G with n vertices, that is, ABC(G) ≤(2n- 4)2~(1/2)/2+(2n-4)~(1/2)/n-1. We also determine the two-trees with the maximum and the second maximum ABC index.     

The distance coloring of graphs

Let G be a connected graph with maximum degree Δ≥ 3.We investigate the upper bound for the chromatic number χγ(G) of the power graph Gγ.It was proved that χγ(G) ≤Δ(Δ-1)γ-1Δ-2+ 1 =:M + 1,where the equality holds if and only if G is a Moore graph.If G is not a Moore graph,and G satisfies one of the following conditions:(1) G is non-regular,(2) the girth g(G) ≤ 2γ- 1,(3)g(G) ≥ 2γ + 2,and the connectivity κ(G) ≥ 3 if γ≥ 3,κ(G) ≥ 4 but g(G) 6 if γ = 2,(4) Δis sufficiently larger than a given number only depending on γ,then χγ(G) ≤ M- 1.By means of the spectral radius λ1(G) of the adjacency matrix of G,it was shown that χ2(G) ≤λ1(G)2+ 1,where the equality holds if and only if G is a star or a Moore graph with diameter 2 and girth 5,and χγ(G)λ1(G)γ+1 ifγ≥3.     

SU(m+n)SU(m)×SU(n) ISOSCALAR FACTORS AND S(f_1+f_2)S(f_1)×S(f_2) OUTER-PRODUCT ISOSCALAR FACTORS

It is proved that the SU(m+n)SU(m)×SU(n) isoscalar factors (ISF) are equal to the S(f_1+f_2) outer-product ISF of the permutation group. Since the latter only depend on the partition labels, the values of the SU(m+n)SU(m)×SU(n) ISF do not depend on m and n explicitely. Consequently for a f(=f_1+f_2)-particle system, by evaluating the S(f) S(f_1)×S(f_2) outer-product ISF we can obtain all (an infinite number) of the SU (m+n) SU(m)×SU(n) ISF (or the f_2-particle coefficients of fractional parentage) for arbitrary m and n at a single stroke, in stead of one m and one n at a time. A simple method, the eigenfunction method, is given for evaluating the SU(m+n) SU(m)×SU(n) single particle ISF, while the many-particle ISF can be calculated in terms of the outer-product reduction coefficients and the transformation coefficients from the Yamanouchi basis to the S(f_1+f_2) S(f_1)×S(f_2) basis.     

M_φ-type Submodules over the Bidisk

Let H~2(D~2) be the Hardy space over the bidisk D~2,and let M_φ=[(z-φ(w))~2] be the submodule generated by(z-φ(w))~2,where φ(w) is a function in H∞(w).The related quotient module is denoted by N_φ=H~2(D~2)ΘM_φ.In the present paper,we study the Fredholmness of compression operators S_z,S_w on N_φ.When φ(w) is a nonconstant inner function,we prove that the Beurling type theorem holds for the fringe operator F_w on [(z-w)~2]Θ z[(z-w)~2] and the Beurling type theorem holds for the fringe operator Fz on M_φΘwM_φ if φ(0)=0.Lastly,we study some properties of F_w on[(z-w~2)~2]Θz[(z-w~2)~2].     

NECESSARY AND SUFFICIENT CONDITIONS FOR THE EXISTENCE OF PERIODIC SOLUTIONS OF RICCATI'S EQUATION WITH PERIODIC COEFFICIENTS

In this paper, the concept of generalized ω-periodic solution is given for Riccati's equationy'=a(t)y~2 b(t)y c(t)with perriodic coefficients, the relation between generalized ω-periodicsolutions and the characteristic numbers of system x'_1=c(t)x_2, x'_2=-a(t)x_1-b(t)x_2 is indicated, andseveral necessary and sufficient conditions are given using the coefficients. Moreover, in the case of a(t)without zero, the relation between the number of continuous ω-periodic solutions of y'=a(t)y~2 b(t)y c(t) δand the parameter δ is given; thus the problem on the existence of continuous ω-periodic.solutions is basically solved.     

Oblique derivative problem for general Chaplygin-Rassias equations

The present paper deals with the oblique derivative problem for general second order equations of mixed (elliptic-hyperbolic) type with the nonsmooth parabolic degenerate line K_1(y)u_(xx) |K_2(x)|u_(yy) a(x,y)u_x b(x, y)u_y c(x,y)u=-d(x,y) in any plane domain D with the boundary D=Γ∪L_1∪L_2∪L_3∪L_4, whereΓ(■{y>0})∈C_μ~2 (0<μ<1) is a curve with the end points z=-1,1. L_1, L_2, L_3, L_4 are four characteristics with the slopes -H_2(x)/H_1(y), H_2(x)/H_1(y),-H_2(x)/H_1(y), H_2(x)/H_1(y)(H_1(y)=|k_1(y)|~(1/2), H_2(x)=|K_2(x)|~(1/2) in {y<0}) passing through the points z=x iy=-1,0,0,1 respectively. And the boundary condition possesses the form 1/2 u/v=1/H(x,y)Re[λuz]=r(z), z∈Γ∪L_1∪L_4, Im[λ(z)uz]|_(z=z_l)=b_l, l=1,2, u(-1)=b_0, u(1)=b_3, in which z_1, z_2 are the intersection points of L_1, L_2, L_3, L_4 respectively. The above equations can be called the general Chaplygin-Rassias equations, which include the Chaplygin-Rassias equations K_1(y)(M_2(x)u_x)_x M_1(x)(K_2(y)u_y)_y r(x,y)u=f(x,y), in D as their special case. The above boundary value problem includes the Tricomi problem of the Chaplygin equation: K(y)u_(xx) u_(yy)=0 with the boundary condition u(z)=φ(z) onΓ∪L_1∪L_4 as a special case. Firstly some estimates and the existence of solutions of the corresponding boundary value problems for the degenerate elliptic and hyperbolic equations of second order are discussed. Secondly, the solvability of the Tricomi problem, the oblique derivative problem and Frankl problem for the general Chaplygin- Rassias equations are proved. The used method in this paper is different from those in other papers, because the new notations W(z)=W(x iy)=u_z=[H_1(y)u_x-iH_2(x)u_y]/2 in the elliptic domain and W(z)=W(x jy)=u_z=[H_1(y)u_x-jH_2(x)u_y]/2 in the hyperbolic domain are introduced for the first time, such that the second order equations of mixed type can be reduced to the mixed complex equations of first order with singular coefficients. And thirdly, the advantage of complex analytic method is used, otherwise the complex analytic method cannot be applied.     

一类由正四面体和正八面体组成的共轭套中心构型

A new case configuration in R3,the conjugate-nest consisted of one regular tetrahedron and one regular octahedron is discussed.If the configuration is a central configuration,then all masses of outside layer are equivalent,the masses of inside layer are also equivalent.At the same time the following relation between p(r=√3/3ρ is the radius ratio of the sizes)and mass ratio r=～m/m must be satisfied r=-m/m=ρ(ρ+3)(3+2ρ+ρ2)-3/2+ρ(-ρ+3)(3-2ρ+ρ2)-3/2-4.2-3/2ρ-2-4-1ρ-2/2(1+ρ)(3+2ρ+ρ2)-3/2+2(ρ-1)(3-2ρ+ρ2)-3/2-4(2√2)-3ρ,and for any mass ratio T,when mass ratio T is in the open interval(0,0.03871633950…),there exist three central configuration solutions(the initial configuration conditions who imply hamagraphic solutions)corresponding radius ratios are r1,r2,and r3,two of them in the interval(2.639300779…,+∞)and one is in the interval(0.7379549890…,1.490942703…).when mass ratio T is in the open interval(130.8164950…,+∞),in the same way there have three corresponding radius ratios,two of them in the interval(0,0.4211584789…)and one is in the interval(0.7379549890…,1.490942703…).When mass ratio T is in the open interval(0.03871633950…,130.8164950…),there has only one solution T in the interval (0.7379549890…,1.490942703…).     

Periodic Solutions of a Class of Second Order Functional Differential Equations

We obtain sufficient conditions for the existence of periodic solutions of the following second order nonlinear differential equation:ax(t) bx^2k-1(t) cx^2k-1(t) g(x(t-T1),x(t-T2) ) = p(t) = p(t 2π)Our approach is based on the continuation theorem of the coincidence degree, and the priori estimate of periodic solutions.     

Evaluation of Certain Integrals Involving the Product of Classical Hermite's Polynomials Using Laplace Transform Technique and Hypergeometric Approach

In this paper some novel integrals associated with the product of classical Hermite's polynomials ∫_(-∞)~(+∞)(x~2)~mexp(-x~2){Hr (x)}2dx, ∫_0~∞exp(-x~2)H_(2k)(x)H_(2s+1)(x)dx,∫_0~∞exp(-x~2)H_(2k)(x)H_(2s)(x)dx and ∫_0~∞exp(-x~2)H_(2k+1)(x)H_(2s+1)(x)dx,are evaluated using hypergeometric approach and Laplace transform method, which is a different approach from the approaches given by the other authors in the field of special functions. Also the results may be of significant nature, and may yield numerous other interesting integrals involving the product of classical Hermite's polynomials by suitable simplifications of arbitrary parameters.     

Geometry of 2×2 Hermitian matrices over any division ring

Let D be a division ring with an involution-,H2(D) be the set of 2 × 2 Hermitian matrices over D. Let ad(A,B) = rank(A-B) be the arithmetic distance between A,B ∈ H2(D) . In this paper,the fundamental theorem of the geometry of 2 × 2 Hermitian matrices over D(char(D) = 2) is proved:if  :H2(D) → H2(D) is the adjacency preserving bijective map,then  is of the form (X) = tP XσP +(0) ,where P ∈ GL2(D) ,σ is a quasi-automorphism of D. The quasi-automorphism of D is studied,and further results are obtained.     

On Rationality of Generating Function for the Number of Spanning Trees in Circulant Graphs

Let F(x)=∑∞n=1 Tsi,s2,...,sk(n)x^n be the generating function for the number,Ts1bs2,...,sk(n) of spanning trees in the circulant graph Cn(s1,S2,...,Sk).We show that F(x)is a rational function with integer coefficients satisfying the property F(x)=F(l/x).A similar result is also true for the circulant graphs C2n(s1,S2,....,Sk,n)of odd valency.We illustrate the obtained results by a series of examples.     

A CONFORMAL SUPFRUNIFIED THEORY

In this paper we have established a superspace U for supergauge actions, constructed a confermal supergroup SU (2, 2|N) and a conformal extended SU (2, 2|N) supergravity theory. Using the Lagrangian Higgs evolution mechanism under the supergroup SU(2, 2|N)SU(N)actions on the superspace U, we have advanced a SU(2, 2|N)SU superunified theory of a superunited system, discussed the Lagrangian evolution of the superunified theory, and given the fiber bundle geometry of all above mechanisms.     

THE ASYMPTOTIC BEHAVIOUR OF ANALYTIC FUNCTIONS

AIn this paper, the author obtains the following results:(1) If Taylor coeffiients of a function satisfy the conditions:(i),(ii),(iii)A_k=O(1/k) the for any h>0 the function φ(z)=exp{w(z)} satisfies the asymptotic equality the case h>1/2 was proved by Milin.(2) If f(z)=z α_2z~2 …∈S~* and,then for λ>1/2     

A note on the crossed product R(A, α) associated with PSL_2(R)

Given the hyperbolic measure dxdy/y2 on the upper half plane H, the rational actions of PSL2(R) on H induces a continuous unitary representation α of this group on the Hilbert space L2(H, dxdy/y2). Supposing that A = {Mf : f ∈ L∞(H, dxdy/y2)}, we show that the crossed product R(A,α) is of type I. In fact, the crossed product R(A,α) is *-isomorphic to the von Neumann algebra B(L2(P,ν))■LK, where LK is the abelian group von Neumann algebra generated by the left regular representation of K.     

Weighted Integral Means of Mixed Areas and Lengths Under Holomorphic Mappings

This note addresses monotonic growths and logarithmic convexities of the weighted((1-t2)αdt2,-∞α∞,0t1)integral means Aα,β(f,)and Lα,β(f,)of the mixed area(πr2)-βA(f,r)and the mixed length(2πr)-βL(f,r)(0≤β≤1 and0r1)of f(rD)and f(rD)under a holomorphic map f from the unit disk D into the finite complex plane C.