Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gravity and Nonlinear Symmetry Realisation   Application of nonlinear symmetry realisation technique to gravity is
studied. We identify the simplest extensions of the Poincare group suitable for
nonlinear realisation. Among them only one model is suitable for description of
massless spin-2 states. This model, unlike general relativity, describes states
with well-defined mass that lack a linear interaction with the matter states.
We argue that this phenomenon points on a necessity to draw a distinction
between gravitational states with well defined masses and states that
participate in interaction with matter.

29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci