JOHN GREENSTADT

1924 - 2022

GREENSTADT--John Lester, researcher in applied mathematics, died on October 17, 2022. Born in Manhattan on October 8, 1924 to Alice and Morris Greenstadt, he had an older sister, Helen (died 2002) and a younger brother, William. After working on flight and artillery engineering as a WWII Army sergeant, John earned a BA at Brooklyn College (1944) and a PhD in Mathematical Physics at Yale (1953). As a staff scientist at IBM from 1952-1985, he published several important papers in numerical optimization that continue to inform the field. A current researcher hails him as "a great thinker to be memorialized forever." Those who knew him also cherished his sarcastic wit, whimsical humor, gentle consideration, creative talent, and prodigious knowledge of the arts and sciences. He maintained his physical and mental acuity until the end of his life when the death of his beloved wife of over 20 years, Karen Lynn Greenstadt, spurred a decline in his own health. Even in the hospital, he cheered the medical staff with his sardonic jokes. John will be mourned by his brother Bill and niece Amy "Eliza" Greenstadt, as well as Karen's son Paulie Germano and sister Nancy Bush. Two adult children from a previous marriage and a granddaughter also survive him.