is_alternating

is_alternating(k)

Check if a diagram is alternating.

A diagram is alternating if each edge meets consecutive endpoints of alternating parity around crossings.

Parameters:

k (PlanarDiagram) – Planar diagram.

Returns:

True if k is alternating, False otherwise.

Return type:

bool

Examples

>>> from knotpy.notation.pd import from_pd_notation
>>> K = from_pd_notation("X[1,3,2,4]")
>>> is_alternating(K)
True