Theses and Dissertations

Issuing Body

Mississippi State University


Hai Dang

Committee Member

Chuanxi Qian

Committee Member

Mohsen Razzaghi

Committee Member

Mohammad Sepehrifar

Committee Member

Robert Smith

Date of Degree


Original embargo terms

Visible to MSU only for 6 months

Document Type

Dissertation - Campus Access Only



Degree Name

Doctor of Philosophy


James Worth Bagley College of Engineering


Department of Mathematics and Statistics


In this dissertation, we study the existence and multiplicity of positive solutions to classes of one-dimensional singular p-Laplacian problems with nonlinear and intergral boundary conditions when the reaction termis p-superlinear or p-sublinear at infinity. In the p-superlinear case, we prove the existence of a large positive solution when a parameter is small and if, in addition, the reaction term satisfies a concavity-like condition at the origin, the existence of two positive solutions for a certain range of the parameter. In the p-sublinear case, we establish the existence of a large positive solution when a parameter is large. We also investigate the number of positive solutions for the general PHI-Laplacian with nonlinear boundary conditions when the reaction term is positive. Our results can be applied to the challenging infinite semipositone case and complement or extend previous work in the literature.Our approach depends on Amann's fixed point in a Banach space, degree theory, and comparison principles.