On the study of a class of non-linear differential equations on compact Riemannian Manifolds

We study the existence of solutions of the non-linear differential equations on the compact Riemannian manifolds $(M^n,g), n\geq 2$, \Delta_p u + a(x)u^{p-1} = \lambda f(u,x), (E2) where $\Delta_p$ is the $p-$laplacian, with $1Riemannian manifold $(M,g)$, the differential equation ($p=2$) \Delta u + a(x)u = \lambda f(u,x), (E1) where $a(x)$ is a $C^{\infty}$ function defined on $M$ and $f(u,x)$ is a $C^{\infty}$ function defined on $\mathbb{R}\times M$. We show that the equation (E2) has solution $(\lambda,u)$, where $\lambda \in \mathbb{R}$, $u \geq 0$, $u \not\equiv 0$ is a function $C^{1,\alpha}$, $0 < \alpha < 1$, if $f \in C^{\infty}$ satisfies some growth and parity conditions.