On the invariance properties and the hamiltonian of the unified affine electromagnetism and gravitation theories
Asymptotic estimates in Weighted Hölder spaces for a class of elliptic scale-covariant second order operators
Polyhomogeneous solutions of wave equations in the radiation regime
While the physical properties of the gravitational field in the radiation regime are reasonably well understood, several mathematical questions remain unanswered. The question here is that of existence and properties of gravitational fields with asymptotic behavior compatible with existence of gravitational radiation. A framework to study those questions has been proposed by R. Penrose (R. Penrose, “Zero rest-mass fields including gravitation”, Proc. Roy. Soc. London A284 (1965), 159-203), and developed...
Radiation fields
We study the “hyperboloidal Cauchy problem” for linear and semi-linear wave equations on Minkowski space-time, with initial data in weighted Sobolev spaces allowing singular behavior at the boundary, or with polyhomogeneous initial data. Specifically, we consider nonlinear symmetric hyperbolic systems of a form which includes scalar fields with a nonlinearity, as well as wave maps, with initial data given on a hyperboloid; several of the results proved apply to general space-times admitting conformal...
On the characteristic initial value problem for nonlinear symmetric hyperbolic systems, including Einstein equations
We consider a characteristic initial value problem for a class of symmetric hyperbolic systems with initial data given on two smooth null intersecting characteristic surfaces. We prove existence of solutions on a future neighborhood of the initial surfaces. The result is applied to general semilinear wave equations, as well as the Einstein equations with or without sources, and conformal variations thereof.
Solutions of the constraint equations in general relativity satisfying "hyperboloidal boundary conditions"
Abstract We prove existence of the solutions of the constraint equations satisfying "hyperboloidal boundary conditions" using the Choquet-Bruhat-Lichnerowicz-York conformal method and we analyze in detail their differentiability near the conformal boundary. We show that generic "hyperboloidal initial data" display asymptotic behaviour which is not compatible with Penrose's hypothesis of smoothness of ℐ. We also show that a large class of "non-generic" initial data satisfying...
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