Tunes of or referring to a trumpet, horn, etc, with no valves or keys, on which only notes in the harmonic series of the keynote can be received is often a commutative monoid with id element 0. It is just a totally free monoid on 1 generator. This commutative monoid https://safeherbalsupplementsdailyuse.game.blog/2025/08/18/best-ayurvedic-brand-in-india-discover-cureayu-health-products/