<< we take a (complex conjugate!) pair of intersection points, ... >> Um --- interactive demo for dummies, anybody? WFL On 5/26/19, Adam P. Goucher <apgoucher@gmx.com> wrote:
Every pair of cleanly nested ellipses can be converted to a pair of circles under a suitable projective transformation. Specifically, we take a (complex conjugate!) pair of intersection points, and map them to the two circular points at infinity using a projective transformation with real coefficients:
https://en.wikipedia.org/wiki/Circular_points_at_infinity
So both of the questions:
*Arbitrary* (cleanly nested) ellipses? Don't they both need to be circles under the same projection?
are true, because they're equivalent.
Best wishes,
Adam P. Goucher
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