What mathematical relationship specifically defines a set of accompanying frequencies as harmonics?

Answer

They are exact integer multiples of the fundamental frequency.

Harmonics are a specific subset of overtones characterized by their precise mathematical spacing; their frequencies must be an integer multiple (n times) of the fundamental frequency (f0).

What mathematical relationship specifically defines a set of accompanying frequencies as harmonics?

#Videos

Music Theory | What is the Overtone Series? - YouTube

Soundvibrationharmonicovertone