Eigenvalue estimates and maximum principle for Lane–Emden systems, and applications to poly-Laplacian equations

This paper deals with explicit upper and lower bounds for principal eigenvalues and the maximum principle associated to generalized Lane–Emden systems (GLE systems). Regarding the bounds, we generalize a well-known upper estimate for the first eigenvalue of linear scalar problems on general domains to the case of strongly coupled GLE systems with [Formula: see text] equations on smooth domains. The explicit lower estimate we obtain is also used to derive a maximum principle to GLE systems relying in terms of quantitative ingredients. Furthermore, as applications of the previous results, upper and lower estimates for the first eigenvalue of weighted poly-Laplacian eigenvalue problems with [Formula: see text] weights [Formula: see text] and Navier boundary condition are obtained. Moreover, a strong maximum principle depending on the domain and the weight function for scalar problems involving the poly-Laplacian operator is also established.