Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Observation and origin of the $\Delta$-manifold in Si:P $\delta$-layers
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
18
The categories of this paper are: econ