Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Accelerating gradient projection methods for $\ell_1$-constrained signal
  recovery by steplength selection rules
8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat