Marshall Harvey Stone
Born: 8 April 1903 in New York, USA
Died: 9 Jan 1989 in Madras, India
Marshall Stone's father was a distinguished lawyer and the family tradition would have had him follow his father's subject. He studied at Harvard from 1919 to 1922, then was appointed an instructor at Harvard for session 1922/23 to see whether he would enjoy teaching mathematics and whether he would take his mathematical studies further.
Indeed he did rapidly decide that he wanted to pursue a career in mathematics and studied for his doctorate under Birkhoff. His doctorate was awarded in 1926 for a thesis entitled Ordinary Linear Homogeneous Differential Equations of Order n and the Related Expansion Problems. By 1925 he was appointed to Columbia University, in 1927 to Harvard. During this period Stone's interests followed very much those of his research supervisor Birkhoff. He published eleven papers on the theory of orthogonal expansions between 1925 and 1928. In these papers a special role is played by expansions in terms of the eigenfunctions of linear differential operators.
Although he would return to Harvard again in 1933, Stone first accepted a post at Yale from 1931 to 1933. Back at Harvard in 1933 he was promoted to full professor there in 1937.
During these years Stone's research took a number of
directions. From 1929 he worked on self-adjoint operators in Hilbert space and included
his results in a major publication of a 600 page book Linear transformations
in Hilbert space and their applications to analysis.
In 1932 he
proved results on spectral theory, arising
from group theoretical methods
in quantum mechanics, which
had been conjectured by Weyl.
Then in 1934 he published two papers on Boolean algebras. He made
this study while attempting to understand more deeply the basics underlying his
results on spectral theory.
One particularly important result proved by Stone during this period was a substantial generalisation of Weierstrass's results on uniform approximation of continuous functions by polynomials. This result is now known as the Stone-Weierstrass theorem.
During World War II Stone undertook secret war work and then in 1946 he left Harvard to take up the chairmanship of the mathematics department at the University of Chicago. He did an outstanding job in returning this famous research school to the eminence it had attained earlier by making appointments such as Weil, Chern and Mac Lane.
From 1952 Stone stepped down as head of department in favour of Mac Lane but he remained at Chicago until he retired in 1968. His interests, which included cooking, are described in [1]:-
Of all Stone's many interests his love of travel was surely dominant. He began to travel when he was quite young and was on a trip to India when he died. ... Marshall Stone was a man with a very broad outlook and a wide range of interests who seems to have thought rather deeply about a number of issues. ... here was an unusually thoughtful man with a high degree of penetration and insight. ... he seemed well endowed with a quality which I can only describe as wisdom.