Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Is dark matter a phantom ?   We show that Einstein's equations in a non-standard gauge have vacuum
solutions with an asymptotically flat rotation curve as it is observed in the
dark halos of galaxies. Introducing a material disk into this model we find a
matter density in accordance with the Tully-Fisher relation.

4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg