Issue 1, Volume 30, April 2005

2005 · Open access

1. STOCHASTIC PROCESSES INDEXED BY URBANIK CONVOLUTION ALGEBRAS NGUYEN VAN THU, CAO VAN NUOI PDF

   ▸ Abstract

   The aim of the present paper is to study a class of second order stochastic processes indexed by Urbanik convolution algebras. We prove their spectral representation which stands for an analogue of that of processes indexed by hypergroups. Moreover, we show that they can be reduced to $*_{\alpha}$-correlated processes.

   1-13
2. A BOUNDED 2-HYPERCONVEX SPACE FAILING TO HAVE THE FIXED POINT PROPERTY FOR A STRICTLY NON-EXPANSIVE MAP NGUYEN NHUY PDF

   ▸ Abstract

   It was shown in [3] that if $\lambda < 2$, then any bounded $\lambda$-hyperconvex space has the fixed point property for non-expansive maps. In this note we construct an example of a bounded 2-hyperconvex space with the fixed point free for any iteration of a strictly non-expansive map.

   15-26
3. UNIFORM NORMAL STRUCTURE AND FIXED POINTS OF NONEXPANSIVE MAPS IN A GENERAL TOPOLOGICAL SPACE $(X, \tau)$ WITH A $\tau$-SYMMETRIC FUNCTION M. AAMRI, D. EL MOUTAWAKIL PDF

   ▸ Abstract

   The main purpose of this paper is to define the concept of uniform normal structure and give some new fixed point theorems of nonexpansive maps in a general topological space $(X, \tau)$ with a $\tau$-symmetric function.

   27-33
4. ON MAXIMAL SUBGROUPS IN DIVISION RINGS BUI XUAN HAI, LE KHAC HUYNH PDF

   ▸ Abstract

   In this work we discuss three conjectures, raised in [3] on maximal subgroups in division rings. Recently M. Mahdavi-Hezavehi gave a negative answer to Conjecture 3 (see below) by constructing a counterexample in the division ring of real quaternions. Here, we show that the other conjectures have a positive answer for division rings of quaternions of characteristics different from 2. The description of all solvable maximal subgroups of the division ring of real quaternions is also given.

   35-43
5. ON THE REPRESENTATIVE THEOREMS FOR ONE-DIMENSIONAL ITERATIVE ARRAYS OF FINITE AUTOMATA PHAM TRA AN PDF

   ▸ Abstract

   In this paper we show that there are representative theorems (or supply-demand theorems) for one-dimensional iterative arrays of finite automata and for one-dimensional iterative arrays of finite automata with a time-variant structure. Some applications are considered.

   45-57
6. A CERTAIN SUBCLASS OF P-VALENTLY ANALYTIC FUNCTIONS WITH NEGATIVE COEFFICIENTS OF COMPLEX ORDER AJAB AKBARALLY, MASLINA DARUS PDF

   ▸ Abstract

   The object of this paper is to show some properties of functions belonging to a subclass $M_p(A,B, b, n)$ (where $b$ is a complex number with $\mathrm{Re}(b) > 0$ and $A$ and $B$ are two arbitrary constants with $−1\leq B < A \leq 1)$. Coefficient estimates and some distortion theorems for this class of functions are found. Radii of close-to-convexity, starlikeness and convexity are derived. An application to fractional calculus is given.

   59-68
7. SUFFICIENT CONDITIONS FOR STRONG STABILITY OF NONLINEAR TIME-VARYING CONTROL SYSTEMS WITH STATE DELAY NGUYEN MANH LINH, VU NGOC PHAT, TA DUY PHUONG PDF

   ▸ Abstract

   This paper deals with a strong stability problem of a class of nonlinear time-varying control systems with state delays. Under appropriate growth conditions on the nonlinear perturbation, new sufficient conditions for the strong stabilizability are established based on the global null-controllability of the nominal linear system. These conditions are presented in terms of the solution of a standard Riccati differential equation. A constructive procedure for finding feedback stabilizing controls is also given.

   69-86
8. SOME REMARKS ON THE NORMALITY OF A FAMILY OF HOLOMORPHIC MAPS INTO THE PROJECTIVE SPACE PHAM HOANG HIEP PDF

   ▸ Abstract

   We study the normality of a family of holomorphic maps from domain in $\mathbf{C}^n$ into the projective space. The main results of the paper is a generalization of a recent result of Z. H. Tu in [Tu].

   87-94
9. THE SOLUTION OF ONE CLASS OF DUAL EQUATIONS INVOLVING HANKEL TRANSFORM NGUYEN VAN NGOC PDF

   ▸ Abstract

   The aim of the present work is to propose a method for investigating and solving one class of dual integral equations involving Hankel transfom.

   95-102