Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An invariance principle for stationary random fields under Hannan's
  condition   We establish an invariance principle for a general class of stationary random
fields indexed by $\mathbb Z^d$, under Hannan's condition generalized to
$\mathbb Z^d$. To do so we first establish a uniform integrability result for
stationary orthomartingales, and second we establish a coboundary decomposition
for certain stationary random fields. At last, we obtain an invariance
principle by developing an orthomartingale approximation. Our invariance
principle improves known results in the literature, and particularly we require
only finite second moment.

3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg