Transverse string topology and the cord algebra
  We define a coalgebra structure for open strings transverse to any framed codimension 2 submanifold. When the submanifold is a knot in R^3, we show this structure recovers a specialization of the Ng cord algebra, a non-trivial knot invariant which is not determined by a number of other knot invariants. 
Somnath Basu, Jason McGibbon, Dennis Sullivan, Michael Sullivan
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