International Journal of Mathematics and Mathematical Sciences 
Volume 2008 (2008), Article ID 527106, 5 pages
doi:10.1155/2008/527106
Research Article

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
Received 9 October 2007; Accepted 19 January 2008

Recommended by Sehie Park

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.