MacTutor
Professor Henry Abel Dye passed way suddenly on November 26, 1986, the victim of a massive heart attack. Although he had suffered many health problems over the preceding decade, those who knew Henry were shocked by the abruptness with which he left us.
Henry was born on Valentine's Day in 1926 in the upstate New York town of Dunkirk. He attended Rensselaer Polytechnic Institute and then went on to the University of Chicago, where he earned his M.S. (1947) and Ph.D. (1950), the latter under the supervision of I.E. Segal. Henry's first academic appointment was as a Bateman Fellow at Caltech for two years followed by an additional year as an Instructor there. He spent 1952-1953 at the Institute for Advanced Study in Princeton and then accepted appointment as an Assistant Professor of Mathematics at the University of Iowa. In 1956, he moved to USC as an Associate Professor and then back to Iowa in 1959. Finally, in 1960 he joined the UCLA faculty as Professor of Mathematics.
The mathematical research of Henry Dye was concentrated in the areas of operator algebras and ergodic theory, in both of which he made fundamental contributions. His first published paper, "The Radon Nikodym theorem for finite rings of operators", contained important results which led to many advances in the theory of von Neumann algebras, for example, the non-commutative integration theory of I.E. Segal and J. Dixmier and the modular theory of von Neumann algebras. In other papers concerning operator algebras, he showed that the unitary group and the projection lattice of a von Neumann factor each completely determine the algebraic structure of that factor. His most important research work is contained in two papers, "On groups of measure preserving transformations. I, II", in which he introduced the notions of weak equivalence of ergodic group actions and of the full group associated to an ergodic group action. He proved the astounding theorem that there is only one ergodic finite measure preserving transformation group up to weak equivalence. These papers, after being ignored for about a decade as being too difficult to assimilate, in part because they imported von Neumann algebra notions into ergodic theory and in part because the ideas were so entirely new, have proved to be the basis of a whole new chapter in ergodic theory: they represent the first important step in the modern development of non-commutative ergodic theory. Owing to remarkable later progress in the structure theory of von Neumann algebras, similar ideas are now understood to lie at the heart of the orbit analysis of ergodic transformation groups and the structure theory of almost finite dimensional factors. This discussion is enough to indicate the importance of Henry Dye's research. He published few papers, but the influence of the mathematical ideas he developed is still being felt. We should also mention that he was instrumental in founding the research group in non-commutative harmonic analysis at UCLA. Under his leadership, this group grew to receive the highest respect from the international community of specialists in this area.
As a teacher of graduate students, Henry was superb. His lectures were lucid and elegant, and he spoke without benefit of notes. Henry's research students learned a lot from him about mathematical culture. He would not tolerate superficiality or pretentiousness. If a student were to produce some mathematics that was wrong or trivial, he would let that student down quite firmly, but would always be careful to leave the student's self-esteem intact. His opinions were usually punctuated with hilarious quips, or with outrageous puns delivered deadpan. Indeed, this addiction to puns came out in everything he did, even in the most solemn of University committees.
And Henry was very active on the University scene. He served the UCLA Mathematics Department as Administrative and as Graduate Vice Chair and was Department Chair from 1975 to 1978. He served on the Committee on Privilege and Tenure at UCLA (1963-66) and Statewide (1968-70), in each case chairing the committee during the last year of his term. He served two terms on the UCLA Council on Academic Personnel (1978-79 and 1982-85). Henry always heard the call of duty and always did it with a great deal of grace. Indeed, during the last year of his life, although in poor health, he was writing reports for the department's eight-year review. His fatal attack came in a parking structure the day before Thanksgiving as he was preparing to go home following a day of work on one of these reports.
Henry Dye's passing has left a great gap in the hearts of his family and friends. He is survived by his wife Eugenie, the Student Affairs Officer in the Communication Studies Program at UCLA, his son John, an Assistant Professor of Mathematics at CSUN, his daughter Constance Phillips of Fresno, and three grandchildren, Dane, Christopher, and Colleen Phillips. He will be missed by all who were fortunate enough to have known him.
William Arveson
Robert Blattner
Masamichi Takesaki
Henry was born on Valentine's Day in 1926 in the upstate New York town of Dunkirk. He attended Rensselaer Polytechnic Institute and then went on to the University of Chicago, where he earned his M.S. (1947) and Ph.D. (1950), the latter under the supervision of I.E. Segal. Henry's first academic appointment was as a Bateman Fellow at Caltech for two years followed by an additional year as an Instructor there. He spent 1952-1953 at the Institute for Advanced Study in Princeton and then accepted appointment as an Assistant Professor of Mathematics at the University of Iowa. In 1956, he moved to USC as an Associate Professor and then back to Iowa in 1959. Finally, in 1960 he joined the UCLA faculty as Professor of Mathematics.
The mathematical research of Henry Dye was concentrated in the areas of operator algebras and ergodic theory, in both of which he made fundamental contributions. His first published paper, "The Radon Nikodym theorem for finite rings of operators", contained important results which led to many advances in the theory of von Neumann algebras, for example, the non-commutative integration theory of I.E. Segal and J. Dixmier and the modular theory of von Neumann algebras. In other papers concerning operator algebras, he showed that the unitary group and the projection lattice of a von Neumann factor each completely determine the algebraic structure of that factor. His most important research work is contained in two papers, "On groups of measure preserving transformations. I, II", in which he introduced the notions of weak equivalence of ergodic group actions and of the full group associated to an ergodic group action. He proved the astounding theorem that there is only one ergodic finite measure preserving transformation group up to weak equivalence. These papers, after being ignored for about a decade as being too difficult to assimilate, in part because they imported von Neumann algebra notions into ergodic theory and in part because the ideas were so entirely new, have proved to be the basis of a whole new chapter in ergodic theory: they represent the first important step in the modern development of non-commutative ergodic theory. Owing to remarkable later progress in the structure theory of von Neumann algebras, similar ideas are now understood to lie at the heart of the orbit analysis of ergodic transformation groups and the structure theory of almost finite dimensional factors. This discussion is enough to indicate the importance of Henry Dye's research. He published few papers, but the influence of the mathematical ideas he developed is still being felt. We should also mention that he was instrumental in founding the research group in non-commutative harmonic analysis at UCLA. Under his leadership, this group grew to receive the highest respect from the international community of specialists in this area.
As a teacher of graduate students, Henry was superb. His lectures were lucid and elegant, and he spoke without benefit of notes. Henry's research students learned a lot from him about mathematical culture. He would not tolerate superficiality or pretentiousness. If a student were to produce some mathematics that was wrong or trivial, he would let that student down quite firmly, but would always be careful to leave the student's self-esteem intact. His opinions were usually punctuated with hilarious quips, or with outrageous puns delivered deadpan. Indeed, this addiction to puns came out in everything he did, even in the most solemn of University committees.
And Henry was very active on the University scene. He served the UCLA Mathematics Department as Administrative and as Graduate Vice Chair and was Department Chair from 1975 to 1978. He served on the Committee on Privilege and Tenure at UCLA (1963-66) and Statewide (1968-70), in each case chairing the committee during the last year of his term. He served two terms on the UCLA Council on Academic Personnel (1978-79 and 1982-85). Henry always heard the call of duty and always did it with a great deal of grace. Indeed, during the last year of his life, although in poor health, he was writing reports for the department's eight-year review. His fatal attack came in a parking structure the day before Thanksgiving as he was preparing to go home following a day of work on one of these reports.
Henry Dye's passing has left a great gap in the hearts of his family and friends. He is survived by his wife Eugenie, the Student Affairs Officer in the Communication Studies Program at UCLA, his son John, an Assistant Professor of Mathematics at CSUN, his daughter Constance Phillips of Fresno, and three grandchildren, Dane, Christopher, and Colleen Phillips. He will be missed by all who were fortunate enough to have known him.
William Arveson
Robert Blattner
Masamichi Takesaki
This University of California obituary is available at THIS LINK