overstrands#

overstrands(k)#

Return a partition of endpoints into sets that belong to the same overstrand.

Overstrand relation:
  • At each crossing, pair the two over-passing endpoints.

  • Along arcs, pair twins.

Returns:

A list of sets (each set is an overstrand’s endpoints).

Parameters:

k (PlanarDiagram | OrientedPlanarDiagram)