... polytropicfluids, see for example Landau and Lifshitz (1987b).Foundations of High-Energy AstrophysicsMario VietriTHE UNIVERSITY OF CHICAGO PRESS Chicago and London1.8. DISCONTINUITY 19Even ... Astrophysics titles available from the University of Chicago Press Inner Space / Outer SpaceEdward Kolb, Michael Turner, Keith Olive, and David Seckel, editors (1985)Theory of Neutron Star MagnetospheresCurtis ... acertain element of mass and follow it in its motion, DX/Dtexpresses the variation of X with time, just as we would seeit if we straddled the element of mass in question. Because of this, the operator...