Workshop From
geometry to numerics
IHP, Paris, 20-24
November 2006
Darragh Walsh (Cork
Univ., Ireland)
Non-uniqueness
in conformal formulations of the Einstein Constraints
The conformal method is the
simplest and most widely used method for generating solutions of
Einstein's constraint equations. Numerical results by Pfeiffer and York
have shown that there is a parabolic branching of solutions as initial
data is varied in the extended conformal thin sandwich model. We derive
identical results analytically using techniques from bifurcation theory
and show that in the scalar case parabolic branching behaviour results
from a poor choice of scaling that leads to linearisation instability.
The implications of these results for evolution schemes will also be
discussed.
[slides]
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