Propagation and cancellation of singularities in a class of Fuchsian operators and their perturbations (Q2468980)

Summary: We obtain some new necessary conditions for wavefront propagation in the noninvolutive Fuchsian operator class \(t\partial ^{2}/\partial t^{2}+\lambda (x,D_{x})\partial /\partial t+\beta (x,D_{x})\). The point of view here is to show that cancellation of propagation of a new singularity in some semilinear systems can be arranged by means of Fuchsian perturbation admitting exact (left and right) microlocal parametrices.