Electronic Journal of Differential Equations (Nov 2019)
Existence, characterization and number of ground states for coupled equations
Abstract
This article concerns the existence, characterization and number of ground states for the system consisting of m coupled semilinear equations $$\displaylines{ -\Delta u_i +\lambda u_i =\sum_{j=1}^m k_{ij} \frac{q_{ij}}{p+1}|u_j|^{p_{ij}}|u_i|^{q_{ij}-2}u_i, \quad x\in \Omega,\cr u_i \in H^1_0(\Omega), \quad i=1,2,\ldots,m. }$$ We extend the characterization results obtained by Correia [5,6] to the above problem. Also we give a new characterization of the ground states, which provides a more convenient way for finding or checking ground states. This study may be the first result not only positive ground states but also for semi-trivial ground states, and it shows that the positive ground state is unique for some special cases.