Chongming+Xu

In this paper, we shall systematically study on the practical and useful research objects in 1PN level and in multiple reference systems by means of comparing with Newtonian counterpart. We divide the research objects into two kinds: with limited degrees of freedom and unlimited degrees of freedom. For the system with limited degrees of freedom we introduce DSX (Damour-Soffel-Xu) formalism to describe the system in terms of the mass- and spin- multiple moments (compact support BD moments) defined in the local coordinates system and the tidal moments. The traslational equations and the rotational equations of motion expressed by multiple moments and tidal moments are shown with bilinear form. The application of DSX in the satellite motion and binary systems are mentioned. We also discuss the special case in limited degrees of freedom, i.e. quasi-rigid body which is the Newtonian counterpart (rigid body ( 6 degrees of freedom)). For the systems with unlimited degrees of freedom, we consider the relativistic theory of elastic body (solid state) and the relativistic hydrodynamic equations and thermodynamic equations for nonperfect fluid in multiple coordinate systems. We also discuss the special case in nonperfect fluid: quasi-incompressible fluid (PN liquid). In the whole paper we introduce our work in brief to show what we have done and have to be done to cause our colleague to pay the attention.
 * Some **** Research Objects in General Relativity - multiple moments, quasi-rigid body, elastic body, fluid, quasi-incompressible fluid and others **
 * Chongming Xu, Purple Mountain Observatory; Nanjing Normal University **