Invariants of the combined nonlinear Schrödinger equation under noninstantaneous medium response (Q1878755)

The authors find invariants of self-interactions of supershort-range pulses in the equation \[ \frac{\partial A}{\partial z}+\nu\frac{\partial A}{\partial \eta}+iD_2\frac{\partial^2 A}{\partial^2\eta }+ D_3\frac{\partial^3 A}{\partial^3\eta} \] \[ +i\alpha_{2\omega}P_{2\omega}A^*+i\alpha_0P_0A+ \frac{\alpha_2}{\omega} \frac{P_{2\omega}A^*}{\partial \eta} +\frac{\alpha_0}{\omega}\frac{P_0A}{\partial \eta}=0 \] with the corresponding initial and boundary conditions.