Were Mark Krein and Lev Pontryagin from the same country?
Mark Krein Mark Grigorievich Krein (Ukrainian: Марко Григорович Крейн , Russian: Марк Григо́рьевич Крейн ; 3 April 1907 – 17 October 1989) was a Soviet Jewish mathematician, one of the major figures of the Soviet school of functional analysis. He is known for works in operator theory (in close connection with concrete problems coming from mathematical physics), the problem of moments, classical analysis and representation theory.
Mark Regev Mark Regev (Hebrew: מארק רגב‎ ‎ , ) (born 1960) is an Israeli diplomat and civil servant, and the Ambassador of Israel to the United Kingdom since April 2016. Prior to that, he was the chief spokesman for the Prime Minister of Israel, a position he held from 2007 to 2015. Originally from Australia, he moved to Israel in 1982.