Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Theory of Gravitation Covariant under $Sp(4, \mathbf{R})$}   We present a Lagrangian theory of gravitation that develops some ideas
proposed several years ago. It is formulated on the 10-dimensional space
$\mathcal{S}$ of the local Lorentz frames (tetrads) and it is covariant under
the symplectic group $Sp(4, \mathbf{R})$, locally isomorphyic to the anti-de
Sitter group $SO(2, 3)$. The corresponding transformation formulas contain a
constant $ \ell$, besides the light velocity $c$. We also assume the covariance
under the "total dilatations" of all the coordinates of the tangent spaces of
$\mathcal{S}$. These symmetries, that we may call "augmented Lorentz
covariance", are spontaneously broken and the corresponding (generalized)
Goldstone fields, that we call "augmentons", behave as the components of a
5-vector of $SO(2, 3)$. Its square can be interpreted as the Brans-Dicke scalar
field, that describes a variable gravitational coupling. The source of the
augmentonic fields is provided by the Dirac fields. Finally, we discuss the
physical relevance of the theory and its possible further developments.

37
The categories of this paper are: supr-con
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
20
The categories of this paper are: acc-phys
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph