Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An elementary proof of Takagi's theorem on the differential composition
  of polynomials   I give a short and completely elementary proof of Takagi's 1921 theorem on
the zeros of a composite polynomial $f(d/dz) \, g(z)$.

5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
7
The categories of this paper are: hep-th