Flux-conserving hyperbolic systems and two-dimensional evaporating black holes

A class of semi-linear hyperbolic systems in 1+1 dimensions was investigated several years ago by Ori and Gorbonos. This class, to which we shall refer as "flux-conserving systems", exhibits a variety of interesting mathematical properties. Here we demonstrate how the formalism of flux-conserving systems can be applied to the problem of black-hole evaporation in 1+1-dimensions. More specifically, we show how the semiclassical CGHS field equations may be approximated by a certain flux-conserving system.