What Greek mathematician who spend most of his professional life in Germany lends his name to the Vitali–Carathéodory theorem?
Vitali–Carathéodory theorem In mathematics, the Vitali–Carathéodory theorem is a result in real analysis that shows that, under the conditions stated below, integrable functions can be approximated in L from above and below by lower- and upper-semicontinuous functions, respectively. It is named after Giuseppe Vitali and Constantin Carathéodory.
Ernst Hellinger Ernst David Hellinger (September 30, 1883 – March 28, 1950) was a German mathematician.