Vietnam Journal
of
MATHEMATICS

Volume 29, Number 1, 2001


1

Detection of Cavities in Solids and Solutions of Elliptic Equations and Systems
Dang Dinh Ang

1

2

A Note on the Property of Infinitely Differentiable Functions
Hoang Mai Le

15

3

On the Mohebi-Radjabalipour Conjecture
Mingxue Liu

19

4

The Bundle Structure of Spherical Non-Commutative Tori
Chun-Gil Park

27

5

Some Properties on Marginal Extensions and the Baer-Invariant of Groups
M. R. R. Moghaddam, A. R. Salemkar, and A. Gholami

39

6

Common Fixed Points for Condensing and Compact Mappings
Tran Thi Lan Anh

47

7

Calibrated Foliations and Invariant Metrics
Vu Thi Thu Ha

53

8

Generalized Indices of Graphs
Zhou Bo

67

9

Weighted Inequalities for Multi-Dimensional Hardy Operators
Yves Rakotondratsimba

71

10

Characterization of Singular Integral Equations
Nguyen Tan Hoa

79

11

Stability Radii of Linear Functional Differential Equations
Nguyen Khoa Son and Pham Huu Anh Ngoc

85

12

A-Decomposability of the Modular Invariants of Linear Groups
Nguyên Huu Viêt Hung and Trân Ngoc Nam

91