Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Recognition of the First Observational Evidence of an Extrasolar
  Planetary System   With 20-20 hindsight, it is now possible to say that the first observational
indication -- by any means -- of the existence of an extrasolar planetary
system came almost a century ago when van Maanen discovered and noted the
spectrum of the nearest single white dwarf to Earth.

0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph