Conformal bounds for the first eigenvalue of the (p, q) -Laplacian system

Consider (M, g) as an m-dimensional compact connected Riemannian manifold without boundary. In this paper, we investigate the first eigenvalue ₁, ₏, ₐ of the (p, q) -Laplacian system on M. Also, in the case of p, q >n we will show that for arbitrary large ₁, ₏, ₐ there exists a Riemannian metric of volume one conformal to the standard metric of S^m.