Incompressibility Criteria for Spun-normal Surfaces

  title={Incompressibility Criteria for Spun-normal Surfaces},
  author={Nathan M. Dunfield and Stavros Garoufalidis},
We give a simple sufficient condition for a spun-normal surfa ce in an ideal triangulation to be incompressible, namely that it is a vertex sur face with non-empty boundary which has a quadrilateral in each tetrahedron. Whi le t is condition is far from being necessary, it is powerful enough to give two new re sults: the existence of alternating knots with non-integer boundary slopes, and proof of the Slope Conjecture for a large class of 2-fusion knots.