I’m interested in solving nonlinear elliptic boundary value problems of the type $$ -a\Delta u + f\left(u\right) = 0, \\ u\big\vert_\Gamma = u_0 $$ by Newton’s method when its convergence is global and monotonic. Could you advice some references concerning this problem, containing proofs of global convergence?
Newton's method takes the form $$ -a\,\Delta u + f\left(\widetilde u\right) + f'\left(\widetilde u\right)\left(u - \widetilde u\right) = 0 $$ where $\widetilde u$ is the previous approximation for the solution.