Andrzej Ehrenfeucht

Andrzej Ehrenfeucht (, born August 8, 1932) is a Polish American mathematician and computer scientist. He formulated the Ehrenfeucht–Fraïssé game, using the back-and-forth method given by Roland Fraïssé in his thesis. The Ehrenfeucht–Mycielski sequence is also named after him.

Ehrenfeucht married Alfred Tarski's daughter Ina Tarski. In 1971 he was a founding member of the Department of Computer Science at the University of Colorado. Ehrenfeucht is currently teaching and doing research at the University of Colorado, where he runs the project "breaking away" together with Patricia Baggett. The project aims at raising high school students' interest in mathematics and technology with hands-on projects.

Two of his students, Eugene Myers and David Haussler, were prominent contributors to the sequencing of the human genome. Haussler and Myers, along with Harold Gabow, Ross McConnell and Grzegorz Rozenberg spoke at a two-day symposium in honor of his 80th birthday, which was organized at the University of Colorado in 2012.

Two journal issues have come out in his honor, one at his 65th birthday in Lecture Notes in Computer Science, and one at his 80th in Theoretical Computer Science.