Topology Seminar: Ayaka Shimizu (Hiroshima University), 'The Reductivity of Knot Projections'

Event Date: 

Tuesday, March 5, 2013 -
3:30pm to 4:30pm

Event Location: 

  • 4607B South Hall

Event Contact: 

Daryl Cooper
Email: cooper@math.ucsb.edu

We introduce the reducivity of knot projections which represents how reduced a knot projection is. The reducivity of a knot projection P is the minimal number of "inverse-half-twisted splices" needed to obtain a reducible knot projection from P. In this talk we show that every knot projection has the reducivity four or less. To give more sharp estimation, we consider unavoidable sets of regions for reduced knot projections.