Approximation theory investigates how complex functions or data can be represented by simpler mathematical entities—such as polynomials, splines, wavelets or ...

Approximation theory of linear operators investigates the systematic approximation of functions by sequences of linear mappings acting on function spaces. Central to the field are families of positive ...

Covers asymptotic evaluation of integrals (stationary phase and steepest descent), perturbation methods (regular and singular methods, and inner and outer expansions), multiple scale methods, and ...