Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Norm-variation of ergodic averages with respect to two commuting
  transformations   We study double ergodic averages with respect to two general commuting
transformations and establish a sharp quantitative result on their convergence
in the norm. We approach the problem via real harmonic analysis, using recently
developed methods for bounding multilinear singular integrals with certain
entangled structure. A byproduct of our proof is a bound for a two-dimensional
bilinear square function related to the so-called triangular Hilbert transform.

11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics