IN MEMORIAM: MICHAEL MORLEY, 1930–2020

Michael Darwin Morley, aged 90, Emeritus Professor of Mathematics at Cornell University, passed away October 12, 2020. Morley’s groundbreaking 1965 paper Categoricity in Power was the beginning of modern model theory and laid the foundation for decades of future developments. Morley was born September 29, 1930 in Youngstown, Ohio and received his B.S. degree in mathematics from Case Institute of Technology in 1951. In 1952, he began graduate work at the University of Chicago joining an energetic group of young logicians including William Howard, John Myhill, Anil Nerode, Raymond Smullyan, Stanley Tennenbaum, and the undergraduate Paul Cohen. While at the University of Chicago he met his future wife Vivienne Brenner, a fellow graduate student who finished her thesis on singular integrals under Antoni Zygmund in 1956. They were a devoted couple for over 50 years. Saunders Mac Lane served as his formal advisor at the University of Chicago. Mac Lane refused to grant a Ph.D. for Morley’s early work on saturated models, but helped arrange for Morley’s employment from 1955 to 1961 at the University of Chicago’s Laboratory for Applied Sciences, where he considered military applications of mathematics. Much of Morley’s work on saturated models was discovered independently by Robert Vaught and Morley left Chicago in 1961 to work with Vaught at Berkeley, first as a visiting graduate student and later as an Instructor. Together they published their independent development of saturated models in [26]. This paper built on Barni Jónsson’s development of the notion of uncountable universal-homogeneous models in universal algebra. Its innovations included a) replacing substructure with elementary substructure, and thus universally axiomatizable theories with first order theories, b) introducing special models so as to avoid the reliance on using the GCH (introduced by Hausdorff) to study universal models, and c) the general proof of the uniqueness of saturated models in a given regular cardinality.