We invite investigators to contribute to this special issue with original articles as well as with review articles that will contribute to the interplay between the theory of function spaces and its various applications in such branches of mathematics as differential and integral equations, optimization and control theory, variational problems, and geometry of various classes of Banach function spaces and its applications. Potential topics include, but are not limited to:

• Theory of various classes of function spaces: Musielak-Orlicz spaces, among them, variable exponent Lebesgue spaces; Lorentz type spaces; Marcinkiewicz spaces; Cesàro spaces and Cesàro -Orlicz spaces; Calderon-Lozanovski BMO spaces; Sobolev type spaces; and modullation spaces
• Operators between the spaces mentioned above (embedding theorems, multiplication and composition operators, etc.)
• Applications of function spaces to differential and integral equations
• Geometry of function spaces as well as of abstract Banach spaces, optimization and control theory, variational problems, and generalized inverses of operators
• Applications of geometry of function spaces to fixed point theory, best approximation problems, and so forth

Before submission authors should carefully read over the journal’s Author Guidelines, which are located at http://www.hindawi.com/journals/aaa/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/aaa/funs/ according to the following timetable: