Degree-sequence invariance for chromatic-symmetric-function-equivalent unicyclic graphs

Determine whether there exist two connected unicyclic graphs with a cycle of length greater than three, different degree sequences, and identical chromatic symmetric functions.

Background

The paper presents a conjecture asserting that, for connected unicyclic graphs with either a 3-cycle and an odd number of vertices or a cycle of length at least four, equality of chromatic symmetric functions forces equality of the degree sequence, the number of non-trivial rooted trees, and the number of internal edges. This conjecture had been verified computationally only through 16 vertices.

The authors then isolate the degree-sequence component as a specific unresolved existence question for cycles of length greater than three. The question concerns whether the chromatic symmetric function can fail to distinguish degree sequences in that broader unicyclic setting.

References

However, it is not known whether there exist two unicyclic graphs with different degree sequences that have the same CSF with $c > 3$.

The Chromatic Symmetric Function for Unicyclic Graphs  (2505.06486 - Bingham et al., 10 May 2025) in Section 7, Examples and data