Functional differential equations have received attention since the 1920's. Within that development, boundary value problems have played a prominent role in bot

This open access book presents a comprehensive survey of modern operator techniques for boundary value problems and spectral theory, employing abstract boundary

Boundary value problems for elliptic differential-difference equations have some astonishing properties. For example, unlike elliptic differential equations, th

This volume provides an introduction to the properties of functional differential equations and their applications in diverse fields such as immunology, nuclear

This book introduces the method of lower and upper solutions for ordinary differential equations. This method is known to be both easy and powerful to solve sec