Kyungpook Mathematical Journal is an international journal devoted to significant research concerning all aspects of mathematics. The journal publishes research papers covering pure mathematics and applied mathematics as well as the applications of mathematics in different branches of science such as chemistry, physics, engineering, biological sciences, computer and information sciences, and other related fields. The journal has a preference for papers having a broad interest. The footnotes to the paper should include the 2000 Mathematics Subject Classification representing the primary and secondary subjects of the article. The classifications are accessible from http://www.ams.org/msc.

Department of Mathematics, Kyungpook National University

Korean