Ehlers' and Rudolph's generalization of Born rigidity is analyzed and some properties of the corresponding flow field are derived. We investigate if at the center of motion pseudorigidity reduces to Born rigidity and give some weak criteria for determining if a given motion is pseudo rigid.

The relation between quasirigidity andL-rigidity in space-times of constant nonzero curvature and in space-times with small curvature (weak fields) is studied. The covariant expansion of bitensors… Expand

We calculate the force between two well-separated bodies in a fully dynamic system of two extended bodies up to and including the second post-Newtonian approximation (PNA). We use the iteration… Expand

A new definition of rigidity,L-rigidity, in general relativity is proposed. This concept is a special class of pseudorigid motions and therefore it depends on the chosen curveL. It is shown that, for… Expand

Dixon's approach to describe the dynamics of extended bodies in metric theories of gravity is elaborated. The exact, general relation between the center-of-mass 4-velocity and the 4-momentum is… Expand

Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences

1970

Definitions are proposed for the total momentum vector pα and spin tensor Sαβ of an extended body in arbitrary gravitational and electromagnetic fields. These are based on the requirement that a… Expand

Einleitung p. 1. - Erstes Kapitel. Die Kinematik des starren Korpers. § 1. Der starre Korper der alten Mechanik p. 6. § 2. Die Differentialbedingungen der Starrheit p. 11. § 3. Die… Expand