On the application of linear methods to the approximation by polynomials of functions which are solutions of Fredholm integral equations of the second kind. I

An approximate solution for Volterra integral equations of the second kind in space with weight function

“…[3] For any kernel k(x, y) ∈ L 2 p [0, 2π], if the linear polynomial operator U n of order n is defined in L 2 p(x) and if the function f (x) ∈ L 2 p(x) , then U n 2π 0 k(., y)f (y)dy; x = 2π 0 U n [k(., y); x]f (y)dy.…”