Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On digital simply connected spaces and manifolds: a digital simply
  connected 3-manifold is the digital 3-sphere   In the framework of digital topology, we study structural and topological
properties of digital n-dimensional manifolds. We introduce the notion of
simple connectedness of a digital space and prove that if M and N are homotopy
equivalent digital spaces and M is simply connected, then so is N. We show that
a simply connected digital 2-manifold is the digital 2-sphere and a simply
connected digital 3-manifold is the digital 3-sphere. This property can be
considered as a digital form of the Poincar\'e conjecture for continuous
three-manifolds.

33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
26
The categories of this paper are: bayes-an
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph