Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Uniqueness of static vacuum Einstein metrics and the Bartnik quasi-local
  mass   We analyse the issue of uniqueness of solutions of the static vacuum Einstein
equations with prescribed geometric or Bartnik boundary data. Large classes of
examples are constructed where uniqueness fails. We then discuss the
implications of this behavior for the Bartnik quasi-local mass. A variational
characterization of Bartnik boundary data is also given.

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The categories of this paper are: q-fin
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The categories of this paper are: cond-mat
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The categories of this paper are: adap-org
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The categories of this paper are: astro-ph
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The categories of this paper are: stat
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-th
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The categories of this paper are: patt-sol
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The categories of this paper are: math-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: funct-an
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: chao-dyn