Leo Zippin was an American mathematician. His parents were Bella Salwen and Max Zippin who immigrated to New York City from the Ukraine

Ukraine

Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...

 in 1903.

Education

He did his undergraduate and graduate work at University of Pennsylvania

University of Pennsylvania

The University of Pennsylvania is a private, Ivy League university located in Philadelphia, Pennsylvania, United States. Penn is the fourth-oldest institution of higher education in the United States,Penn is the fourth-oldest using the founding dates claimed by each institution...

 in 1929. His doctoral adviser was John Robert Kline

John Robert Kline

John Robert Kline was a US-American Professor of Mathematics at the University of Pennsylvania from 1920 to 1955. A Ph.D. student of Robert Lee Moore, he was Guggenheim Fellow in 1925, later Chairman of the Department of Mathematics from 1933 to 1954 and Thomas A...

. He was the author of The Uses Of Infinity and together with Deane Montgomery, the monograph Topological Transformation Groups. In 1952, he, along with Andrew M. Gleason and Deane Montgomery

Deane Montgomery

Deane Montgomery was a mathematician specializing in topology who was one of the contributors to the final resolution of Hilbert's fifth problem in the 1950s. He served as President of the American Mathematical Society from 1961 to 1962....

 solved Hilbert's fifth problem

Hilbert's fifth problem

Hilbert's fifth problem, is the fifth mathematical problem from the problem-list publicized in 1900 by mathematician David Hilbert, and concerns the characterization of Lie groups. The theory of Lie groups describes continuous symmetry in mathematics; its importance there and in theoretical physics...

.