7.3. Directed Harmonic Relationships

A relation rule accepts a directed pair of modal states. It may preserve a root or mode, move a root by an interval or circle-of-fifths step, move between specific modes, or combine several alternatives.

The General Purpose profile covers four useful corners: same or +5-semitone root movement crossed with same or next-mode movement. The two Brightening experiments move through Phrygian → Aeolian → Dorian → Mixolydian → Ionian → Lydian without wrapping.

These names describe harmonic policy, not an automatic emotional arc. Library coverage, track arrangement, and the available graph determine what a complete Mix actually becomes.