This book presents a systematic overview of approximation by linear
combinations of positive linear operators, a useful tool used to
increase the order of approximation. Fundamental and recent results from
the past decade are described with their corresponding proofs. The
volume consists of eight chapters that provide detailed insight into the
representation of monomials of the operators Ln, direct and inverse
estimates for a broad class of positive linear operators, and case
studies involving finite and unbounded intervals of real and complex
functions. Strong converse inequalities of Type A in terminology of
Ditzian-Ivanov for linear combinations of Bernstein and
Bernstein-Kantorovich operators and various Voronovskaja-type estimates
for some linear combinations are analyzed and explained. Graduate
students and researchers in approximation theory will find the list of
open problems in approximation of linear combinations useful. The book
serves as a reference for graduate and postgraduate courses as well as a
basis for future study and development.