In mathematics, the Borel–Carathéodory theorem in complex analysis shows that an analytic function may be bounded by its real part, it is named for Émile Borel and Constantin Carathéodory, was a Greek mathematician who spent most of his professional career in which country?
Borel–Carathéodory theorem:  It is named for Émile Borel and Constantin Carathéodory. Constantin Carathéodory: Constantin Carathéodory (Greek: Κωνσταντίνος Καραθεοδωρή "Konstantinos Karatheodori"; 13 September 1873 – 2 February 1950) was a Greek mathematician who spent most of his professional career in Germany.
Germany