Mathematician John Stallings died last year at 73

San Francisco - Berkeley - Psychologist Jack Block, 85, has died Positive prospects for California's green businesses, study finds Chancelllor Birgeneau announces senior-management transition plans, as Brostrom accepts UCOP position UC to cut fewer freshmen from fall 2010 enrollment NSF grant to launch world's first open-source genetic parts production facility - John Robert Stallings Jr., a professor emeritus of mathematics at the University of California, Berkeley, who made seminal contributions to geometric group theory and topology, died Nov. 24, 2008, from prostate cancer at his home in Berkeley. He was 73. Accomplished but modest, Stallings was perhaps best known for his partial solution to the generalized Poincare Conjecture, reached several days after hearing that it had been solved, but not knowing how, according to UC Berkeley colleague Robion Kirby, professor of mathematics. The Poincare Conjecture, proposed by the French mathematician Henri Poincare in 1900, generalizes to all higher dimensions the observation that all two-dimensional surfaces on which every loop can be shrunk to a point without snagging is equivalent to a sphere. Any smooth object without holes is mathematically equivalent to a sphere, while the surface of a teacup, for example, is not, because a loop around the handle cannot be shrunk to a point.