Abstract and Applied Analysis
Volume 6 (2001), Issue 5, Pages 299-308

On the projection constants of some topological spaces and some applications

Entisarat El-Shobaky,1 Sahar Mohammed Ali,2 and Wataru Takahashi2

1Department of Mathematics, Faculty of Science, Ain Shams University, Cairo, Egypt
2Department of Mathematical and Computing Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552, Japan

Received 13 May 2001

Copyright © 2001 Entisarat El-Shobaky et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We find a lower estimation for the projection constant of the projective tensor product XY and the injective tensor product XY, we apply this estimation on some previous results, and we also introduce a new concept of the projection constants of operators rather than that defined for Banach spaces.