Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Web is missing an essential part of infrastructure: an Open Web
  Index   A proposal for building an index of the Web that separates the infrastructure
part of the search engine - the index - from the services part that will form
the basis for myriad search engines and other services utilizing Web data on
top of a public infrastructure open to everyone.

8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat