On the hyperbolicity of Einstein's and other gauge field equations
It is shown that gauge field equations, including the Yang-Mills and Einstein's field equations, if suitably understood imply symmetric hyperbolic systems of propagation equations for any choice of gauge. In the equations appear certain freely specifiable ''gauge source functions'', which govern the propagation of the gauge off a suitable initial surface. The method is discussed in detail for the ''regular conformal field equations'' for the conformally rescaled metric field in general relativity. Besides the coordinate and the frame gauge source functions may be given here arbitrarily the Ricci-scalar which constitutes the gauge source function which determines the propagation of the conformal factor. The technique has been applied to analyse the existence of radiative space-times by the author [''On Purely Radiative Space-Times'', ibid. 103, 35-65 (1986)]. Furthermore it led to the first general results on the global existence and the asymptotic behaviour of solutions of Einstein's field equations with positive cosmological constant [see the author, ''On the existence of n-geodesically complete or future complete solutions of Einstein's field equations with smooth asymptotic structure''. Preprint, Hamburg (1986)].
scientific article; zbMATH DE number 3944407
scientific article