Closed 3-braids with unknotting number one

Geometry & Topology
Event time: 
Thursday, February 12, 2009 - 9:30am to Wednesday, February 11, 2009 - 7:00pm
206 LOM
Josh Greene
Speaker affiliation: 
Princeton University
Event description: 

I will discuss the characterization of the closed 3-braid knots with unknotting number one. Any such knot is close to being alternating, and an alternating one has an unknotting crossing in its alternating diagram. The proof uses Heegaard Floer homology and Donaldson’s Theorem A.

Special note: 
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