Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: The study of variability in engineering design, an appreciation and a
  retrospective
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph