Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Equilateral quantum graphs and boundary triples   The aim of the present paper is to analyse the spectrum of Laplace and Dirac
type operators on metric graphs. In particular, we show for equilateral graphs
how the spectrum (up to exceptional eigenvalues) can be described by a natural
generalisation of the discrete Laplace operator on the underlying graph. These
generalised Laplacians are necessary in order to cover general vertex boundary
conditions on the metric graph. In case of the standard (also named
``Kirchhoff'') boundary conditions, the discrete operator is the usual
combinatorial Laplacian.

10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
19
The categories of this paper are: eess
18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
5
The categories of this paper are: gr-qc
6
The categories of this paper are: astro-ph