Andrzej Ehrenfeucht

Andrzej Ehrenfeucht (born August 8, 1932, in Wilno) is a Polish American mathematician and computer scientist who earned his PhD from the University of Warsaw in 1960 with a dissertation applying games to definability and decidability in ordinal theory. He formulated the Ehrenfeucht-Fraïssé game, extending the back-and-forth method of Roland Fraïssé's thesis into a technique for comparing the expressive power of logical structures that became a standard tool in finite model theory and descriptive complexity; the Ehrenfeucht-Mycielski sequence also bears his name. In 1971 he became a founding member of the Department of Computer Science at the University of Colorado Boulder, where his students included Eugene Myers and David Haussler, who went on to contribute to the sequencing of the human genome.