Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Well Posed Reduced Systems for the Einstein Equations   We review some well posed formulations of the evolution part of the Cauchy
problem of General Relativity that we have recently obtained. We include also a
new first order symmetric hyperbolic system based directly on the Riemann
tensor and the full Bianchi identities. It has only physical characteristics
and matter sources can be included. It is completely equivalent to our other
system with these properties.

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The categories of this paper are: q-alg
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The categories of this paper are: plasm-ph
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The categories of this paper are: supr-con
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The categories of this paper are: eess
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The categories of this paper are: econ
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The categories of this paper are: q-fin
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The categories of this paper are: bayes-an
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The categories of this paper are: atom-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-ex
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The categories of this paper are: cs
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The categories of this paper are: cmp-lg
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The categories of this paper are: math-ph
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The categories of this paper are: hep-th
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The categories of this paper are: hep-lat