If energy input in these zones is balanced, we derive some characteristics from the modality structure itself. We call tonicity of the grouping the F-potential reduced by the entropy of the sounding. The distribution of the F-potentials in the tonality determines certain levels of particular groupings. The transition from one level to another one results in a tension. Harmonic functions Harmonic functions are groupings from a harmonic variety with extreme properties.
Tonic function is the grouping with the maximum tonicity.
Dominant function is the grouping with the maximum positive continuity towards the tonic. Subdominant function is the grouping with the maximum negative continuity, i.e. the maximum positive continuity in the direction from the tonic. Phrygian function , is the grouping with the maximum impulse towards the tonic from above.