Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spacetime-bridge solutions in vacuum gravity   Spacetimes, which are representations of a bridge-like geometry in gravity
theory, are constructed as vacuum solutions to the first order equations of
motion. Each such configuration consists of two copies of an asymptotically
flat sheet, connected by a bridge of finite extension where tetrad is
noninvertible. These solutions can be classified into static and non-static
spacetimes. The associated SO(3,1) invariant fields, namely the metric, affine
connection and field-strength tensor, are all continuous across the
hypersurfaces connecting the invertible and noninvertible phases of tetrad and
are finite everywhere. These regular spacetime-bridge solutions do not have any
analogue in Einsteinian gravity in vacuum.

22
The categories of this paper are: chao-dyn
4
The categories of this paper are: cond-mat
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con