@article{Liu2026, 
author = {Minghui Liu and Jiqiang Jiang and Guoqiang Chen and Na Li and Lishan Liu and Yonghong Wu},
title = {Positive solutions for Hadamard fractional differential equations with sign changing nonlinearity and paremeters},
year = {2026},
journal = {Electronic Research Archive},
volume = {34},
number = {3},
pages = {1785-1808},
keywords = {Hadamard fractional derivative, fractional differential equation, fixed-point theorems, reducing order technique, parameter},
url = {https://www.sciopen.com/article/10.3934/era.2026080},
doi = {10.3934/era.2026080},
abstract = {This study investigates boundary value problems for nonlinear fractional differential equations. The differential operator is interpreted in the Hadamard sense and is coupled with a nonlinear term that involves the fractional derivative of the unknown function. The existence and multiplicity of positive solutions were established by a reducing-order technique based on the Guo–Krasnoselskii fixed-point theorem. Also, some examples are presented to illustrate the validity of our main results.}
}