Nonlinear systems in various function spaces constitute basic mathematical models of real world phenomena. Related problems are of great interest to mathematicians, physicists, biologists, medical scientists, and engineers, even to economists and sociologists, because most systems coming from the real world are inherently nonlinear in nature. This special issue is focused on latest achievements in nonlinear systems in function spaces. It will consider both the state-of-the-art theoretical research and important recent advances in applications to biomedical sciences, control theory, and engineering.

We cordially invite researchers to contribute original research articles as well as review articles devoted to the study of the nonlinear systems in various function spaces. We are interested in articles that explore qualitative theory, stability, approximation, asymptotic behavior, periodicity, almost periodicity, and almost automorphic behavior of nonlinear systems. We also encourage authors to submit articles developing mathematical tools and methods of the analysis and interpretation of nonlinear mathematical models from the real world especially from biomedical sciences, control theory, and engineering. Potential topics include, but are not limited to:

• Theory of function spaces
• Nonlinear systems with discrete or continuous time
• Modeling, theory, and algorithms for problems of biomedical sciences
• Modeling, theory, and algorithms for problems of biomedical sciences
• Topological and monotone methods
• Related theory of operator
• Nonlinear optimal and control problems
• Mathematical models in engineering

Before submission authors should carefully read over the journal’s Author Guidelines, which are located at http://www.hindawi.com/journals/jfsa/guidelines/. Prospective authors should submit an electronic copy of their complete manuscript through the journal Manuscript Tracking System at http://mts.hindawi.com/submit/journals/jfs/nlfs/ according to the following timetable: