Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Yang-Mills Instantons in the Gravitational Instanton Backgrounds   The simplest and the most straightforward new algorithm for generating
solutions to (anti) self-dual Yang-Mills (YM) equation in the typical
gravitational instanton backgrounds is proposed. When applied to the Taub-NUT
and the Eguchi-Hanson metrics, the two best-known gravitational instantons, the
solutions turn out to be the rather exotic type of instanton configurations
carrying finite YM action but generally fractional topological charge values.

22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci