Decartes' Perfect Lens
Abstract
Description
We give a new, elementary, purely analytical development of \textsc{Descartes}' theorem that a smooth connected surface is a perfect focusing lens if and only if it is a connected subset of the ovoid obtained by revolving a cartesian oval around its axis of symmetry.
12 pages; proof of the exceptional cases to Drucker's theorem elaborated; one new importante reference is added; typos corrected
12 pages; proof of the exceptional cases to Drucker's theorem elaborated; one new importante reference is added; typos corrected