Boundary Value Problems
Volume 2009 (2009), Article ID 507671, 25 pages
Research Article

First-Order Singular and Discontinuous Differential Equations

1Department of Mathematics, Belmont University, 1900 Belmont Blvd., Nashville, TN 37212, USA
2Department of Mathematical Analysis, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain

Received 10 March 2009; Accepted 4 May 2009

Academic Editor: Juan J. Nieto

Copyright © 2009 Daniel C. Biles and Rodrigo López Pouso. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We use subfunctions and superfunctions to derive sufficient conditions for the existence of extremal solutions to initial value problems for ordinary differential equations with discontinuous and singular nonlinearities.