to_dt_notation

to_dt_notation(k)

Serialize a knot/link diagram to DT notation.

For knots, returns a single tuple of signed odd labels. For links, returns a tuple of tuples (one per component), following the usual conventions: - Label even indices along the traversal at each crossing on the incoming over endpoint. - The sign of the paired odd label is positive/negative based on the local crossing orientation.

Parameters:

k – Planar or oriented diagram.

Returns:

tuple – For a knot, (l1, l2, ..., l_{2n}). For a link, ((...), (...), ...).

Raises:

ValueError – If the diagram is not a knot/link in a way compatible with DT.

Return type:

Tuple[Tuple[int, …], …] | Tuple[int, …]