IJPAM: Volume 21, No. 2 (2005)

BEST APPROXIMATION IN A CLASS OF
ORDERED NORMED SPACES WITHOUT
A PRE-ORDER RELATION

H. Mohebi$^1$, H. Sadeghi$^2$
$^{1,2}$Department of Mathematics
University of Kerman
Kerman, IRAN
$^1$e-mail: hmohebi@mail.uk.ac.ir
$^2$e-mail: hsadeghi@graduate.uk.ac.ir


Abstract.We examine best approximation by closed sets in a class of ordered normed spaces with a relation which is not necessarily a pre-order relation. We use downward and upward sets as tools for examination of best approximation by closed sets. We first study best approximation properties of these sets.

Received: April 10, 2005

AMS Subject Classification: 41A65, 46B40, 41A50

Key Words and Phrases: best approximation, downward set, upward set, relatively downward set, relatively upward set, proximinal set

Source: International Journal of Pure and Applied Mathematics
ISSN: 1311-8080
Year: 2005
Volume: 21
Issue: 2