Note 51 — Chapter I · A SHORT HISTORY OF METAGEOMETRY.
Reading edition
The anharmonic ratio of four numbers, p, q, r, s, is defined as
(p - q).(r - s) / (p - r).(q - s).
Reading edition
The anharmonic ratio of four numbers, p, q, r, s, is defined as
(p - q).(r - s) / (p - r).(q - s).