Precup, RaduGheorghiu, Calin-IoanRodríguez López, Jorge2025-12-192025-12-192022Rodríguez-López, J., Precup, R., Gheorgjiu, C. (2022). On the localization and numerical computation of positive radial solutions for ϕ -Laplace equations in the annulus. "Electronic Journal of Qualitative Theory of Differential Equations", 47, 1-221417-3875https://hdl.handle.net/10347/44601The paper deals with the existence and localization of positive radial solutions for stationary partial differential equations involving a general ϕ-Laplace operator in the annulus. Three sets of boundary conditions are considered: Dirichlet–Neumann, Neumann–Dirichlet and Dirichlet–Dirichlet. The results are based on the homotopy version of Krasnosel’skiĭ’s fixed point theorem and Harnack type inequalities, first established for each one of the boundary conditions. As a consequence, the problem of multiple solutions is solved in a natural way. Numerical experiments confirming the theory, one for each of the three sets of boundary conditions, are performed by using the MATLAB object-oriented package Chebfun.engCreative Commons Attribution (CC BY) licenseϕ-Laplace operatorRadial solutionPositive solutionFixed point indexHarnack type inequalityNumerical solutionjournal articleopen access