Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Freud's Identity of Differential Geometry, the Einstein-Hilbert
  Equations and the Vexatious Problem of the Energy-Momentum Conservation in GR   We reveal in a rigorous mathematical way using the theory of differential
forms, here viewed as sections of a Clifford bundle over a Lorentzian manifold,
the true meaning of Freud's identity of differential geometry discovered in
1939 (as a generalization of results already obtained by Einstein in 1916) and
rediscovered in disguised forms by several people. We show moreover that
contrary to some claims in the literature there is not a single (mathematical)
inconsistency between Freud's identity (which is a decomposition of the
Einstein indexed 3-forms in two gauge dependent objects) and the field
equations of General Relativity. However, as we show there is an obvious
inconsistency in the way that Freud's identity is usually applied in the
formulation of energy-momentum "conservation laws" in GR. In order for this
paper to be useful for a large class of readers (even those ones making a first
contact with the theory of differential forms) all calculations are done with
all details (disclosing some of the "tricks of the trade" of the subject).

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The categories of this paper are: cs
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The categories of this paper are: bayes-an
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The categories of this paper are: alg-geom
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The categories of this paper are: astro-ph
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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
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The categories of this paper are: q-bio
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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: hep-th
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The categories of this paper are: acc-phys
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The categories of this paper are: gr-qc
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The categories of this paper are: q-alg
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The categories of this paper are: hep-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: stat