Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Periodic Hamiltonian flows on four dimensional manifolds   We classify the periodic Hamiltonian flows on compact four dimensional
symplectic manifolds up to isomorphism of Hamiltonian S^1 spaces. Additionally,
we show that all these spaces are Kaehler, that every such space is obtained
from a simple model by a sequence of symplectic blowups, and that if the fixed
points are isolated then the space is a toric variety.

0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys