In an effort to increase public appreciation of the importance of mathematics, Cornell University's Department of Mathematics is sponsoring its first annual public lecture as part of the nationwide Math Awareness Month.

On Saturday, April 29, John Hubbard, Cornell professor of mathematics, will give a talk titled "Chaos, Complication and Control." The talk will be given at 1:30 p.m. in Bache Auditorium, Malott Hall, Room 228, which can be reached through the north entrance, facing Bailey Hall.

An internationally renowned researcher, Hubbard is best known for his work on the Mandelbrot set, featured in James Gleick's best-selling book Chaos: Making a New Science. Hubbard also is a popular communicator of mathematics to non-mathematical audiences. In 1998 he gave the first Singapore Mathematical Society Distinguished Visitor Programme Public Lecture, and since then has spoken at the Smithsonian Institution, the Vaudoise Society for Natural Sciences in Lausanne, Switzerland, and in the Science and Society lecture series in Paris. He also is a regular visitor to the chaos and fractals class at Ithaca High School.

Hubbard will show how mathematics underlies every facet of science and technology, from computer games, cellular phones and the Internet, to medical diagnostic tests, the design of new prescription drugs and minimally invasive surgery. Yet most people, he says, have little or no idea what mathematicians do or how their work is used.

Hubbard's talk will explain how a very "simple" differential equation modeling a very ordinary forced damped pendulum can exhibit extraordinarily complicated and unstable behavior. Such pendulums are the basic sub-unit in robots, so mathematical understanding of their behavior can contribute to the design of better robots in industry and even medicine. One challenge for the future, he says, will be to enable complex robots to take advantage of their own instabilities so they can perform like an expert skier rather than like a clumsy beginner.

The same phenomenon of the pendulum, Hubbard says, can be seen in the history of airplane design. Because 19th century engineers identified control with stability, the first airplanes were designed to be extremely stable. But in World War I, pilots found that this stability made it impossible for them to dodge enemy fire. Making airplanes less stable made them safer, because they were easier to control.