As I said before in other writings, a corrective wave has its own motive wave.
For example the A-minor wave of the zigzag pattern is its motive wave. When one looks deeper into the equality principle, one will recognise that it is fair to say that the first leg of a directional multiple-segment price structure is often (not always) equal in length and magnitude to its last segment.
That is really the secret of the equality waves principle.
With that deduction, one can use that principle for both impulse and corrective waves or even any specific price structure or pattern.
Indeed, it is rational to say that there is often equality between the A and C minor waves of a corrective. That is applicable to the flat and zigzag corrective waves. It is also true for a triple zigzag.