Graduate Student Colloquium: Lee Kennard (UCSB), 'Milnor's 'strange but quite elementary proof' of the Hairy Ball Theorem'

Event Date: 

Thursday, April 4, 2013 -
3:30pm to 4:30pm

Event Location: 

  • 6635 South Hall

Event Contact: 

Daryl Cooper


The Hairy Ball Theorem states that an even-dimensional sphere cannot admit a nonvanishing continuous vector field. One fun consequence is that the wind is *not* blowing at some point on the surface of the Earth. There are multiple proofs, but most require a bit of machinery (e.g., homology theory or differential forms). John Milnor provided what he calls a "strange" proof that only uses elementary real analysis.