Background for Homology: The Common Secant, the Cross-Ratio, and Harmonic Sets
摘要
The next transformation we will examine is homology, a special case of the more general projective transformation. Poncelet’s development of homology, a process we can trace from his Notebooks of 1813–1814 through his masterwork, the Traité of 1822, involves several important topics. We present these one at a time, beginning with the common secant.