Unstable Vassiliev Theory
  We construct an inverse system of unstable Vassiliev spectral sequences on the spaces of plumbers' knots, which model the homotopy type of the space of long knots, and show that the limit of these sequences contains the finite type invariants in their usual complexity. Utilizing the cell structure on the discriminant of the spaces of plumbers curves, we extend the notion of Vassiliev derivative to all singularity types of plumbers' curves. 
Chad Giusti
math.AT math.GT