“…Notable results include the paper by Einfeldt et al [34], where it is shown that the Godunov and HLLE schemes are positivity preserving, while the Roe scheme is not, the paper by Batten et al [6] where they showed that the HLLC [139] scheme is positivity preserving with an appropriate choice of wave velocity estimates, the work by Perthame and Shu [116] where they established a general framework to achieve high-order positivity preserving methods for the Euler equations in one and two dimensions, and the book by Bouchut [11] where the conditions on the wave velocities estimates are determined so that the HLLC scheme can also handle vacuum. Areas of interest include the Euler equations (Calgaro et al [14], Hu et al [61], Li et al [87], Zhang and Shu [150,151,152]), shallow water equations [121,71,147,3], magnetohydrodynamics [4,67,40], multiphase flows (Chen and Shu [18]), unstructured meshes (Berthon [8]) and flux-vector splitting methods (Gressier et al [46]), to name just a few. These papers consider standard methods and mostly tackle issues with positivity preserving that arise in high-order methods.…”