Patrick X. Gallagher

Patrick Ximenes Gallagher (January 2, 1935 – March 30, 2019) was an American mathematician who pioneered large sieve theory and invented the larger sieve.

Biography Early life Patrick Ximenes Gallagher was born on January 2, 1935, in Elizabeth, New Jersey to school superintendent Ralph P. Gallagher and elementary school teacher Natalie Forcheimer Gallagher. In 1959, Gallagher received a PhD from Princeton University with a doctoral dissertation entitled Metric Diophantine Approximation in One and Several Dimensions completed under the supervision of Donald C. Spencer.

Career After receiving his doctoral degree, Gallagher served as an instructor at the Massachusetts Institute of Technology from 1959 to 1961. He moved from Columbia to become a member of the Institute for Advanced Study for the 1964-1965 academic year. He retired from Columbia in 2017 and was professor emeritus until his death in 2019. He also applied the large sieve to study the asymptotics of Galois groups of monic integral polynomials of bounded height, improving on results by van der Waerden.

In 1971, he invented the larger sieve.

Family Gallagher met his wife, Minh Chau Gallagher, while he was an instructor at MIT in 1960. They had two sons together.