Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Massles multi gravity: Covariant, stable, two-derivative interacting
  massless multi-graviton theories   We present a general model of interacting metric fields with the sum of
massless non-interacting spin 2 fields as the linear limit. In the
non-interacting limit the model is reduced to a sum of general relativity
actions, with the usual Einstein-Hilbert kinetic term for each metric field.
Until now the accepted view was that such theories are inconsistent since it
has been proven that ghost terms and/or discontinuity in the number of degrees
of freedom at the zero interaction limit, are unavoidable. We do not refute
these results, but instead prove by construction that they do not necessarily
lead to inconsistencies. In particular, our suggested theories are: 1.
Energetically stable, i.e. their Hamiltonian is bounded from below and the
multi-Minkowski metric configuration is the unique ground state. 2. Continuous
in the zero interaction limit so that general relativity solutions are restored
smoothly. 3. Include no higher than two derivative Lagrangian terms. In
addition, the dominant energy condition is maintained with respect to all
metric fields for all field configurations.

1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
6
The categories of this paper are: astro-ph
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th