Conformal mapping, a central concept in complex analysis, involves the transformation of one complex domain onto another while preserving local angles and shapes. This powerful tool has long been used ...

We answer a question raised by M. Chuaqui, P. Duren, and B. Osgood by showing that a conformal mapping of a simply connected domain cannot take two circles onto two proper ellipses.

American Scientist (ISSN 0003-0996) is an illustrated bimonthly magazine about science and technology. Each issue is filled with feature articles written by prominent scientists and engineers, ...