Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Two-dimensional cycle classes on $\overline{\mathcal{M}_{0,n}}$   For each $n\ge5$, we give an $S_n$-equivariant basis for
$H_4(\overline{\mathcal{M}_{0,n}},\mathbb{Q})$, as well as for
$H_{2(n-5)}(\overline{\mathcal{M}_{0,n}},\mathbb{Q})$. Such a basis exists for
$H_2(\overline{\mathcal{M}_{0,n}},\mathbb{Q})$ and for
$H_{2(n-4)}(\overline{\mathcal{M}_{0,n}},\mathbb{Q})$, but it is not known
whether one exists for $H_{2k}(\overline{\mathcal{M}_{0,n}},\mathbb{Q})$ when
$3\le k\le n-6$.

36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci