Partial Differential Equations of Physics by Robert Geroch
Publisher: arXiv 1996
Number of pages: 57
All partial differential equations that describe physical phenomena in space-time can be cast into a universal quasilinear, first-order form. We describe some broad features of systems of differential equations so formulated. Examples of such features include hyperbolicity of the equations, constraints and their roles, how diffeomorphism freedom is manifest, and how interactions between systems arise and operate.
Science Physics Relativity & Gravitation General Relativity