Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Space Time Defects as a Source of Curvature and Torsion   Space time is described as a continuum four-dimensional medium similar to
ordinary elastic continua. Exploiting the analogy internal stress states are
considered. The internal ''stress'' is originated by the presence of defects.
The defects are described according to the typical Volterra process. The case
of a point defect in an otherwise isotropic four-dimensional medium is
discussed showing that the resulting metric tensor corresponds to an expanding
(or contracting) universe filled up with a non-zero energy-momentum density.

8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat