Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Projective Ring Lines and Their Generalisations   We give a survey on projective ring lines and some of their substructures
which in turn are more general than a projective line over a ring.

29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg