International Journal of Mathematics and Mathematical Sciences
Volume 2008 (2008), Article ID 527106, 5 pages
doi:10.1155/2008/527106
Some characterizations of open, closed, and continuous mappings
Navpreet Singh Noorie
and Rajni Bala
Department of Mathematics, Faculty of Physical Sciences, Punjabi University, Patiala 147002, India
Abstract
We obtain new characterizations of open maps in terms of closures, of closed maps in terms of interiors, and of continuous maps in terms of interiors. Further open (closed) onto maps f:X→Y are described in terms of images under f of certain closed (open) sets in X. Continuity of (onto) maps is also characterized in terms of saturated sets.