Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Unimodular Relativity and the Dark Matter Problem   We introduce a modified divergence law for the energy-momentum tensor in the
theory of unimodular relativity. Consequently, an additional equation for the
measure field follows from the divergence of the field equations. The equations
of motion are derived and the weak-field, low-velocity limit is investigated.
It is found that the gravitational acceleration acquires a term that is
proportional to the gradient of the mass density. We show that this term can
provide the additional acceleration observed on astrophysical scales without
the need for dark matter.

30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat