In neo-Riemannian musical theory, a particular collection of triadic chord transformations labeled by P, L, and R can be seen to form a group acting on the set of 24 major and minor triads. There are many other sorts of transformations between chords, and there are other sorts of chords besides major and minor triads.
In his GURM project, Christopher Heitmann sought other collections of chord transformations that would act on sets of chords as a group. He wrote code in both Python and GAP and developed a procedure to sift through a dataset of chord transformations and rule out certain combinations for violating necessary conditions for group structure. He was able to find a pair of chord transformations that acted as a group on a set of triads which included augmented and diminished triads.
Christopher presented his work on April 1, 2023 in a poster session at the Philadelphia Undergraduate Mathematics Conference (PUMC) and in a presentation on April 13, 2023 at the Eastern Pennsylvania and Delaware (EPaDel) Section Meeting of the Mathematical Association of America.