Nieto, Juan J.; Rodríguez-López, Rosana Comparison results and approximation of extremal solutions for second-order functional differential equations. (English) Zbl 1163.34043 J. Nonlinear Funct. Anal. Differ. Equ. 1, No. 1, 67-102 (2007). The authors are interested in the study of a nonlinear second order functional differential equation with periodic boundary conditions. They first consider a linear second order ordinary differential equation subject to a functional perturbation with periodic conditions. They first present some comparison results for the linear equation, then they approach the existence of a solution for this problem. In a second step they develop a monotone method to approximate the solution of the nonlinear equation. Reviewer: Mustapha Yebdri (Tlemcen) Cited in 2 Documents MSC: 34K10 Boundary value problems for functional-differential equations 34K07 Theoretical approximation of solutions to functional-differential equations Keywords:functional differential equations; maximum principle; periodic boundary conditions; iterative technique; upper and lower solutions PDFBibTeX XMLCite \textit{J. J. Nieto} and \textit{R. Rodríguez-López}, J. Nonlinear Funct. Anal. Differ. Equ. 1, No. 1, 67--102 (2007; Zbl 1163.34043)