Arthur Sard (28 July 1909, New York City – 31 August 1980, Basel) was an American mathematician, famous for his work in differential topology and in spline interpolation.
His fame stems primarily from Sard's theorem, which says that the set of critical values of a differential function which has sufficiently many derivatives has measure zero.
[1] Arthur Sard was born and grew up in New York City and spent most of his adult life there.
[3] Sard retired as professor emeritus in 1970 at Queens College and then worked at La Jolla, where he spent five years as a research associate in the mathematics department of the University of California, San Diego.
[1] From 1938 until his death Sard published almost forty research articles in refereed mathematical journals.