Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A remark on convergence almost-everywhere of eigenfunction expansions of
  elliptic operators   In this paper it is proposed a very simple method for estimating the maximal
operator in $L_1$. Using this method one can considerably improve the existing
theorems on convergence almost-everywhere of eigenfunction expansions of an
arbitrary elliptic differential operators with a point spectrum. In particular,
it is obtained a new result on convergence almost-everywhere of spherical
partial sums of the multiple Fourier series of smooth functions.

22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
27
The categories of this paper are: comp-gas