Robert L. Devaney

Robert Luke Devaney (born 1948) is an American mathematician, the Feld Family Professor of Teaching Excellence at Boston University. His research involves dynamical systems and fractals.

Devaney was born on April 9, 1948, and grew up in Methuen, Massachusetts.

Devaney graduated in 1969 from the College of the Holy Cross, and earned his Ph.D. in 1973 from the University of California, Berkeley under the supervision of Stephen Smale. Before joining the faculty at Boston University, he taught at Tufts University, Northwestern University, and the University of Maryland, College Park.

Devaney is known for formulating a simple and widely used definition of chaotic systems, one that does not need advanced concepts such as measure theory. In his 1989 book An Introduction to Chaotic Dynamical Systems, Devaney defined a system to be chaotic if it has sensitive dependence on initial conditions, it is topologically transitive (for any two open sets, some points from one set will eventually hit the other set), and its periodic orbits form a dense set. Later, it was observed that this definition is redundant: sensitive dependence on initial conditions follows automatically as a mathematical consequence of the other two properties.

Devaney hairs, a fractal structure in certain Julia sets, are named after Devaney, who was the first to investigate them.

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