... Telecommunications,Chongqing 400065, China2Key Laboratory of Network Control & Intelligent Instrument, Chongqing University of Posts and Telecommunications, Ministry of Education, Chongqing 400065, China3College ... China3College of Applied Sciences, Beijing University of Technology, Beijing 100124, China4Automation Institute, Chongqing University of Posts and Telecommunications,Chongqing 400065, ChinaCorrespondence ... 1.2 utilizingthe method of upper and lower solutions and Schauder fixed-point theorem. The existence of maximal and minimal solutions for 1.2 is given in Section 4.2. Preliminaries and NotationsFor...