Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Instanton Solution in Tachyon Cosmology   We find an exact classical solution in Euclidean gravity coupled to a scalar
field with a particular form of potential commonly used in tachyon cosmology.
This solution represents a tunneling between two vacua.

12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat
8
The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th