Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: High repetition rate and coherent Free-Electron Laser in the tender
  X-rays based on the Echo-Enabled Harmonic Generation of an Ultra-Violet
  Oscillator pulse
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph