Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Study of the Fundamental Structure of Matter with an Electron-Ion
  Collider   We present an overview of the scientific opportunities that would be offered
by a high-energy electron-ion collider. We discuss the relevant physics of
polarized and unpolarized electron-proton collisions and of electron-nucleus
collisions. We also describe the current accelerator and detector plans for a
future electron-ion collider.

30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci