Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Conformal Einstein equations and Cartan conformal connection   Necessary and sufficient conditions for a space-time to be conformal to an
Einstein space-time are interpreted in terms of curvature restrictions for the
corresponding Cartan conformal connection.

0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin