Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Open Mapping Theorem   It is proved that any surjective morphism $f: \mathbb{Z}^\kappa \to K$ onto a
locally compact group $K$ is open for every cardinal $\kappa$. This answers a
question posed by Karl Heinrich Hofmann and the second author.

3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th