deletion_contraction

deletion_contraction(k, *, contract_bridges=True)

Return terminal diagrams after recursive deletion–contraction.

Parameters:

• k (PlanarDiagram) – Input planar diagram (graph, no crossings).

• contract_bridges (bool) – If False, skip contracting bridges (useful for Tutte T(x,y)).

Returns:

A list of diagrams in which every arc is a loop or a bridge.

Return type:

list[PlanarDiagram]