“…Finally, let us note that asymmetric nonlinearities also surprisingly appear in the study of competing systems of species with large interactions in biology (see [4,6,22]) and the Fučík spectrum of the Dirichlet Laplacian (the Laplace operator u → −Δu with zero Dirichlet boundary conditions) is needed (see [6] for details). Nowadays, there are a number of papers in which authors study the structure of the Fučík spectrum for particular linear differential operators, let us mention here only some of them: [1,2,7,9,14,23,24] for the Dirichlet Laplacian on bounded domains, [3,13,15,16,26,27] for the ordinary differential operators with various boundary conditions (Dirichlet, Neumann, Robin, Navier, periodic, multipoint, integral type).…”