Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hidden Symmerties in Dilaton--Axion Gravity   Four--dimensional Einstein--Maxwell--dilaton--axion system restricted to
space--times with one non--null Killing symmetry is formulated as the
three--dimensional gravity coupled sigma--model. Several alternative
representations are discussed and the associated hidden symmetries are
revealed. The action of target space isometries on the initial set of
(non--dualized ) variables is found. New mulicenter solutions are obtained via
generating technique based on the formulation in terms of the non--dualized
variables.

28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con