Two theorems in catoptrics.
Two general theorems in the theory of mirrors are presented. The first one asserts that a mirror that reflects a parallel beam into a beam with zero mean curvature must be harmonic. The second one provides a universal characterization of the spot diagram of rays from a reflected parallel beam as they intersect a plane orthogonal to their direction of propagation.
Rubinstein
J
J
Department of Mathematics, Technion-Israel Institute of Technology, Haifa. koby@math.technion.ac.il
Wolansky
G
G