Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A gap theorem for free boundary minimal surfaces in the three-ball   We show that, among free boundary minimal surfaces in the unit ball in the
three-dimensional Euclidean space, the flat equatorial disk and the critical
catenoid are characterised by a pinching condition on the length of their
second fundamental form.

18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph