"Soul Theorem" Mathematician Detlef Gromoll Dies at 70

July 15, 2008

Detlef Gromoll (SUNY at Stony Brook), who studied abstract distortions of shapes in three or more dimensions and whose work played a part in the eventual proof of the Poincaré Conjecture, died of a stroke at the end of May. He was 70.

Bruce Kleiner of Yale University credited Gromoll and Jeff Cheeger of New York University with providing one of the cornerstones of Grigori Perelman's 2003 breakthrough. "And it actually shows up in two independent places in Perelman's proof," Kleiner told the New York Times. It is "a really essential ingredient in that work."

In the 1960s and 70s, Gromoll and his collaborators investigated certain surfaces with flat areas or curves but not regions shaped liked saddles. They theorized that the properties of such surfaces, infinite in extent and existing in any number of dimensions, could be deduced from a finite central core. Grommoll suggested calling this region the "soul" of the object.

The result came to be termed the "soul theorem." H. Blaine Lawson Jr. (SUNY at Stony Brook) described it as "a phenomenally beautiful theorem."

Gromoll, born in Germany and educated at the University of Bonn, received a doctorate in 1964. He worked at Princeton University, Mainz University in Germany, the University of California, Berkeley, and the University of Bonn before joining SUNY at Stony Brook, in 1969.

In mathematical collaborations, Cheeger said, Gromoll would fine-tune the wording of every sentence in a paper. "It was a lot of fun," Cheeger said, "but it could be maddening."

Source: New York Times, June 19, 2008.