Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Positive operator measures, generalised imprimitivity theorem, and their
  applications   Given a topological group $G$ and a unitary representation $U$ of $G$, we
consider the problem of classifying the positive operator measures which are
based on a $G$-homogeneous space $X$ and covariant with respect to the
representation $U$. We completely solve the problem in two cases: 1) when $G$
is abelian; 2) when $G$ is not abelian, $X$ has compact stbiliser in $G$ and
the representation $U$ is irreducible. We then give an application of the above
results to the characterisation of covariant position and momentum observables
in quantum mechanics, and to the determination of those covariant position and
momentum observables that are jointly measurable.

15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat