Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Reducible boundary conditions in coupled channels   We study Hamiltonians with point interactions in spaces of vector-valued
functions. Using some information from the theory of quantum graphs we describe
a class of the operators which can be reduced to the direct sum of several
one-dimensional problems. It shown that such reduction is closely connected
with the invariance under channel permutations. Examples are provided by some
"model" interactions, in particular, the so-called delta, delta-prime, and the
Kirchhoff couplings.

23
The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex