Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Long geodesics on convex surfaces   We review the theory of intrinsic geometry of convex surfaces in the
Euclidean space and prove the following theorem: if the surface of a convex
body K contains arbitrary long closed simple geodesics, then K is an isosceles
tetrahedron.

28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat