"Presents a theory of difference and functional equations with continuous argument based on a generalization of the Riemann integral introduced by N.E. Norlund, allowing differentation with respect to the independent variable and permitting greater flexibility in constructing solutions and approximations. Discusses linear transformations that state conditions for convergence of Newton series and Norlund sums!"
". . .interesting. . .. . . .relevant."
". . .a very useful survey. . ..intended for both beginners and specialists."
Operator functions; generalities on difference equations; Norlund Sum, part 1; Norland Sum, part II; the first order difference equation; the linear equation with constant coefficients; linear difference equations with polynomial coefficients.