Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Infinite Charge Algebra of Gravitational Instantons   Using a formalism of minitwistors, we derive infinitely many conserved
charges for the $sl(\infty )$-Toda equation which accounts for gravitational
instantons with a rotational Killing symmetry. These charges are shown to form
an infinite dimensional algebra through the Poisson bracket which is isomorphic
to two dimensional area preserving diffeomorphism with central extentions.

34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
18
The categories of this paper are: econ
2
The categories of this paper are: math