Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A group-theoretical classification of three-tone and four-tone harmonic
  chords   We classify three-tone and four-tone chords based on subgroups of the
symmetric group acting on chords contained within a twelve-tone scale. The
actions are inversion, major-minor duality, and augmented-diminished duality.
These actions correspond to elements of symmetric groups, and also correspond
directly to intuitive concepts in the harmony theory of music. We produce a
graph of how these actions relate different seventh chords that suggests a
concept of distance in the theory of harmony.

30
The categories of this paper are: q-alg
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat