Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Double gauge invariance and covariantly-constant vector fields in Weyl
  geometry   The wave equation and equations of covariantly-constant vector fields (CCVF)
in spaces with Weyl nonmetricity turn out to possess, in addition to the
canonical conformal-gauge, a gauge invariance of another type. On a Minkowski
metric background, the CCVF system alone allows us to pin down the Weyl
4-metricity vector, identified herein with the electromagnetic potential. The
fundamental solution is given by the ordinary Lienard-Wiechert field, in
particular, by the Coulomb distribution for a charge at rest. Unlike the
latter, however, the magnitude of charge is necessarily unity, "elementary",
and charges of opposite signs correspond to retarded and advanced potentials
respectively, thus establishing a direct connection between the
particle/antiparticle asymmetry and the "arrow of time".

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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
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The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: ao-sci
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The categories of this paper are: funct-an
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The categories of this paper are: patt-sol
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The categories of this paper are: supr-con
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The categories of this paper are: chao-dyn
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: nucl-ex
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The categories of this paper are: econ
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The categories of this paper are: nlin
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The categories of this paper are: acc-phys