Slight amplification [Medieval "conversity"]

Just as a slight amplification to the P.C., I.C. (pitch class, interval
class) nomenclature I was talking about in reference to the interesting
Margo Schulter article on "conversities" in Medieval music...

The "conversity" would be an INTERVALLIC inversion where the I.C.'s, of
course would change and would invert or "reciprocate."

In the "real" inversion, however, as in ANY true inversion, the P.C's
would remain invariant...

I believe the idea of "reduction to pitch class" was already discussed
in the article... but it would surely come to the fore with an invariant
P.C. nomenclature...

I don't know if this would fit the theory appropriately or not...

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Joseph Pehrson