Finite convergence and the \(\alpha(G)\geq 9\) case for \(\nu^{(r)}\)

Determine whether, for graphs with stability number \(\alpha(G)\geq 9\), the equality \(\nu^{(\alpha(G)-1)}(G)=\alpha(G)\) holds and whether the hierarchy \(\nu^{(r)}(G)\) has finite convergence for every graph.

Background

The hierarchy ν(r)(G)\nu^{(r)}(G) is based on the more restrictive SOS cones Qn(r)Q_n^{(r)}. The equality at level α(G)1\alpha(G)-1 is known for graphs with α(G)8\alpha(G)\leq 8, but the paper explicitly identifies the extension to larger stability numbers as unresolved. It also distinguishes this issue from the corresponding ϑ\vartheta-hierarchy, for which finite convergence had recently been proved, and states that finite convergence of ν(r)\nu^{(r)} itself was not known.

References

Whether this result holds for \alpha(G)\geq 9 remains an open question. It even remains open whether the hierarchy \nu{(r)}(G) has finite convergence.

Low degree sum-of-squares bounds for the stability number: a copositive approach  (2509.04949 - Vargas et al., 5 Sep 2025) in Section 2.3, immediately after Conjecture 2.1