Benoit Mandelbrot | Star mathematician, 85

Mathematician Benoit Mandelbrot, 85, died of cancer Oct. 14 in Cambridge, Mass. His death was announced by Yale University, where he became a mathematics professor in 1987 after a long career at IBM.

Dr. Mandelbrot was the father of fractals, a term he coined in 1975 to describe a new branch of geometry that seeks to make sense of irregular shapes and processes, from the infinite zigs and zags of a seacoast to erratic fluctuations on Wall Street.

He worked in obscurity for the first decades of his career. With the books Fractals: Form, Chance and Dimension (1977) and The Fractal Geometry of Nature (1982), he became the math world's equivalent of a rock star, drawing standing-room audiences to lectures.

His fractal theory entered popular culture, inspiring a song, novels, and elegant, computer-generated art.

Classical Euclidean geometry describes flat surfaces, but Dr. Mandelbrot wondered about the nature of everything that wasn't flat, such as a cumulus cloud or a lung.

His first major insight stemmed from his attempt in the late 1960s to answer the question "How long is the coast of Britain?" He argued that the answer depended on the size of one's ruler. The more he zoomed in on the shoreline, the more indentations became visible.

Classical geometry could not handle this "roughness," so he developed a new tool, which he later called fractal geometry. Instead of ignoring the disorderly twists of the coast, mathematicians and geographers could now more accurately envision its scope.

- Los Angeles Times