Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A comment on "The Cauchy problem of f(R)- gravity", Class. Quantum
  Grav., 24, 5667 (2007), arXiv:0709.4414   A critical comment on [N. Lanahan--Tremblay and V. Faraoni, 2007, {\it Class.
Quantum Grav.}, {\bf 24}, 5667, arXiv:0709.4414] is given discussing the
well-formulation of the Chauchy problem for $f(R)$-gravity in metric-affine
theories.

26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
17
The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
2
The categories of this paper are: math