Assertion: parabola | /r/CapableOf | lack in apollonius's known works
Facets:
Source sentences:
text: Pappus of Alexandria (died c. 350 CE) is credited with expounding on the importance of the concept of a conic's focus, and detailing the related concept of a directrix, including the case of the parabola (which is lacking in Apollonius's known works).