Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Approximate ML Decision Feedback Block Equalizer for Doubly Selective
  Fading Channels
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
4
The categories of this paper are: cond-mat
11
The categories of this paper are: hep-lat