Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Some Gravitational Instantons   All known gravitational instantons with $\Lambda > 0$ ($S^4, CP^2, S^2 \times
S^2$ and $CP # \overline{CP}^2$) are described. They are all special cases of
the Taub-NUT-$\Lambda$ local solution. Hence they are Type D and are locally
conformably K\"ahler. They all may be expressed in Bianchi IX form and have
four or more Killing vectors.

36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an