Chao Wang, Ph.D., is a Professor in the Department of Mathematics at Yunnan Univer-sity. Dr. Wang has authored the books Theory of Translation Closedness for Time Scales andCombined Measure and Shift Invariance Theory of Time Scales and Applications, both publishedby Springer. His research focuses on the fields of nonlinear dynamic systems, controltheory, fuzzy dynamic equations, fractional differential equations, bifurcation theory,nonlinear analysis, and numerical modeling.Ravi P. Agarwal, Ph.D., is a Professor in the Department of Mathematics at the Texas A&M University-Kingsville. He completed his Ph.D. at the Indian Institute of Technology, Madras, India, in 1973. Dr. Agarwal has authored or co-authored 50 books and 1,750 research articles. His research interests include nonlinear analysis, differential and difference equations, fixed point theory, and generalinequalities.