Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Problems related to a de Bruijn - Erd\H{o}s theorem   De Bruijn and Erd\H{o}s proved that every noncollinear set of n points in the
plane determines at least n distinct lines. We suggest a possible
generalization of this theorem in the framework of metric spaces and provide
partial results on related extremal combinatorial problems.

36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio