Chu, JifengNieto Roig, Juan José2020-06-062020-06-062009Chu, J., Nieto, J. Recent Existence Results for Second-Order Singular Periodic Differential Equations. Bound Value Probl 2009, 540863 (2009). https://doi.org/10.1155/2009/5408631687-2762http://hdl.handle.net/10347/22856We present some recent existence results for second-order singular periodic differential equations. A nonlinear alternative principle of Leray-Schauder type, a well-known fixed point theorem in cones, and Schauder's fixed point theorem are used in the proof. The results shed some light on the differences between a strong singularity and a weak singularity.engCopyright © 2009 J. Chu and J. J. Nieto. 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 citedhttp://creativecommons.org/licenses/by/2.0/Periodic SolutionExistence ResultFixed Point TheoremExistence ConditionTopological Methodjournal article10.1155/2009/5408631687-2770open access