Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On Fano manifolds with a birational contraction sending a divisor to a
  curve   Let X be a smooth Fano variety of dimension at least 4. We show that if X has
an elementary birational contraction sending a divisor to a curve, then the
Picard number of X is smaller or equal to 5.

30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
4
The categories of this paper are: cond-mat
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th