Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Order isomorphisms between bases of topologies   In this paper we will study the representations of isomorphisms between bases
of topological spaces. It turns out that the perfect setting for this study is
that of regular open subsets of complete metric spaces, but we have achieved
some results about arbitrary bases in complete metric spaces and also about
regular open subsets of Hausdorff regular topological spaces.

16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org