⁴⁵ The term fluctuation is not native for Eastern Chant research but has particular importance for my compositional practice. The term as such is developed in a different context in research by Dmitry Tymoczko (see bibliography: 2004, 2008) and used with the same meaning here. I have been using the term in my practice even before encountering Tymoczko’s research, as it is the simplest and most effective wording for this harmony devise that is very typical for Eastern Chant. Similar is the use of the same term by Nguyen (cited below), unrelated to Tymoczko.