The collapse of the Soviet Union had a powerful effect on American mathematicians, crowding them out of jobs.
It brought an influx of Soviet mathematicians to US institutions - and changed the way math is studied and taught in the country, according to new research by University of Notre Dame economist Kirk Doran and a colleague from Harvard.
"In the period between the establishment and fall of communism, Soviet mathematics developed in an insular fashion and along very different specializations than American mathematics," says Doran.
"As a result, some mathematicians experienced few potential insights from the Soviets, while other fields experienced a flood of new mathematicians, theorems and ideas."
During the 70-year communist period, there was little collaboration between Soviet and Western mathematicians - indeed, any communication with American mathematicians was read by authorities and special permission was needed to publish outside the Soviet Union.
"Just as speakers of one language, when separated geographically for many generations, develop separate and different dialects through natural changes over time, so Western and Eastern mathematicians, separated by Stalinist and Cold War political institutions, developed under different influences to the point of achieving very different specializations across the fields of mathematics," says Doran.
The result of the fall of communism was increased competition - and the Americans didn't come out of it terribly well. There was a marked decline in the productivity of American mathematicians whose areas of specialty most overlapped with that of the Soviets, and a fall in the number of top papers they produced.
Similarly, marginal American mathematicians became much more likely to transfer to lower ranked institutions and to significantly reduce their research and scholarship.
There's good news for American students of Soviet émigrés, though: Doran says they showed higher lifetime productivity than students from the same institutions whose advisors came from elsewhere.