Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Estimation of the temperature-density relation in the intergalactic
  medium at $\mathbf{z\sim 2-4}$ via Ly$\mathbf{\alpha}$ forest
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an