Semidiscretization in time for nonlinear Schrödinger-waves equations

In this paper, we are concerned with Crank-Nicolson like schemes for: $ (NLW_\omega ) \frac{1}{\omega^2} \partial_t^2 E_\omega -i\partial_t E_\omega -\D E_\omega =\lambda | E_\omega |^{2\sigma} E_\omega. $ We present two schemes for which we give some convergence results. On of the scheme is dissipative and we describe precisely the dissipation. We prove that the solution of the second scheme fits that of $(NLW_\omega )$ while the first one compute a average value of the solution.