Abstract: | The following work is an extension of our recent paper 10]. We still deal with nonlinear eigenvalue problems of the form in a real Hilbert space ?? with a semi‐bounded self‐adjoint operator A0, while for every y from a dense subspace X of ??, B(y ) is a symmetric operator. The left‐hand side is assumed to be related to a certain auxiliary functional ψ, and the associated linear problems are supposed to have non‐empty discrete spectrum (y ∈ X). We reformulate and generalize the topological method presented by the authors in 10] to construct solutions of (??) on a sphere SR ? {y ∈ X | ∥y∥?? = R} whose ψ‐value is the n‐th Ljusternik‐Schnirelman level of ψ| and whose corresponding eigenvalue is the n‐th eigenvalue of the associated linear problem (????), where R > 0 and n ∈ ? are given. In applications, the eigenfunctions thus found share any geometric property enjoyed by an n‐th eigenfunction of a linear problem of the form (????). We discuss applications to elliptic partial differential equations with radial symmetry. |