Abstract and Applied Analysis 
Volume 2004 (2004), Issue 10, Pages 897-905
doi:10.1155/S1085337504311085

Existence of triple positive periodic solutions of a functional differential equation depending on a parameter

Xi-lan Liu,1 Guang Zhang,2 and Sui Sun Cheng3

 1Department of Mathematics, Yanbei Normal Institute, Datong, Shanxi 037000, China
2Qingdao Polytechnic University, Qingdao, Shandong 266033, China
3Department of Mathematics, National Tsing Hua University, Hsinchu 30043, Taiwan
Received 15 October 2002

Abstract

We establish the existence of three positive periodic solutions for a class of delay functional differential equations depending on a parameter by the Leggett-Williams fixed point theorem.