Shair Ahmad & Marvin Keener 
Differential Equations 

Differential Equations is a collection of papers from the "Eight Fall Conference on Differential Equations" held at Oklahoma State University in October 1979. The papers discuss hyperbolic problems, bifurcation function, boundary value problems for Lipschitz equations, and the periodic solutions of systems of ordinary differential equations. Some papers deal with the existence of periodic solutions for nonlinearly perturbed conservative systems, the saddle-point theorem, the periodic solutions of the forced pendulum equation, as well as the structural identification (inverse) problem for illness-death processes. One paper presents an elementary proof of the work of de Oliveira and Hale, and applies the stability for autonomous systems in the critical case of one zero root. Another paper explains the necessary and sufficient conditions for structural identification prior to application in states of illness-death processes. An illness-death process is a continuous Markov model with n illness (transient) states each having one (and only one) transfer into a death state. The paper examines two theorems whether these apply to an illness-death process under certain given elements. The collection is an ideal source of reference for mathematicians, students, and professor of calculus and advanced mathematics.