Nomos Alpha (Greek: Νόμος α΄) is a piece for solo cello composed by Iannis Xenakis in 1965, commissioned by Radio Bremen for cellist Siegfried Palm, and dedicated to mathematicians Aristoxenus of Tarentum, Évariste Galois, and Felix Klein.
During his lifetime, Xenakis was a vocal critic of modern Western music since the development of polyphony for its diminished set of outside-time structures, especially when compared to folk and the Byzantine musical traditions.
Nomos Alpha consists of 24 sections divided into two layers.
[2] Layer 1 of Nomos Alpha is determined by the 24-element octahedral group isomorphic to the rotations of a cube.
The elements of the set are permutations and the binary operator is composition.