Note on the nodal line of the p -Laplacian. El Amrouss, Abdel R.; El Allali, Zakaria; Tsouli, Najib — 2006 Electronic Journal of Differential Equations (EJDE) [electronic only]
The third order spectrum of the p-biharmonic operator with weight Khalil Ben Haddouch; Najib Tsouli; Zakaria El Allali — 2014 Applicationes Mathematicae We show that the spectrum of Δ ² p u + 2 β · ∇ ( | Δ u | p - 2 Δ u ) + | β | ² | Δ u | p - 2 Δ u = α m | u | p - 2 u , where β ∈ ℝ N , under Navier boundary conditions, contains at least one sequence of eigensurfaces.