Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On polar relative normalizations of ruled surfaces   This paper deals with skew ruled surfaces in the Euclidean space
$\mathbb{E}^{3}$ which are equipped with polar normalizations, that is,
relative normalizations such that the relative normal at each point of the
ruled surface lies on the corresponding polar plane. We determine the
invariants of a such normalized ruled surface and we study some properties of
the Tchebychev vector field and the support vector field of a polar
normalization. Furthermore, we study a special polar normalization, the
relative image of which degenerates into a curve.

9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex