Frederick C. Hennie III, professor emeritus in the MIT Department of Electrical Engineering and Computer Science (EECS), died on Oct. 23. He was 90 years old. An affiliate of MIT EECS for his entire adult life, Hennie is known for influential early work in the theory of computation, as well as work on algorithms and discrete mathematics. As a longtime executive officer for the department, Hennie’s facility for programming languages and databases and his careful approach to highly complex systems made him a valued co-worker and advisor to multiple department…