Set-weighted chromatic symmetric function coefficient-sum conjecture

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Let (G,ω)(G,\omega) be a set-weighted graph with nn vertices and total weight dd, and write

X(G,ω)=∑λ⊢dcλeλ.X_{(G,\omega)}=\sum_{\lambda\vdash d}c_{\lambda}e_{\lambda}.

Let μ≤d\mu\leq d be an integer, viewed as a one-part partition, that is ss-allowable in (G,ω)(G,\omega), and fix j∈{0,…,d−μ}j\in\{0,\dots,d-\mu\}, with j=0j=0 permitted only when μ=d\mu=d. For an acyclic orientation γ\gamma and a generalized 22-step weight map SS, let swts⁡(γ,S)\operatorname{swts}(\gamma,S) and wts⁡(γ,S)\operatorname{wts}(\gamma,S) denote the associated statistics, and let sgn⁡(γ,S)\operatorname{sgn}(\gamma,S) be the sign defined from the first nonempty step of each relevant stable set. Set-weighted coefficient-sum conjecture.

σμ,j(X(G,ω))=(−1)d−n∑swts⁡(γ,S)=(μ,j)S admissible⁡sgn⁡(γ,S),\sigma_{\mu,j}\bigl(X_{(G,\omega)}\bigr)=(-1)^{d-n}\sum_{\substack{\operatorname{swts}(\gamma,S)=(\mu,j)\\ S\ \operatorname{admissible}}}\operatorname{sgn}(\gamma,S),

summed over all acyclic orientations γ\gamma of GG and all γ\gamma-admissible generalized 22-step weight maps SS of GG such that wts⁡(γ,S)=(μ,j)\operatorname{wts}(\gamma,S)=(\mu,j). The conjecture gives a combinatorial interpretation of a broad family of sums of ee-basis coefficients of vertex-weighted chromatic symmetric functions. It extends a known follow-up result of Stanley; in particular, the abstract states that it would give an interpretation for sums with prescribed values of λ1′\lambda'_1 and λ2′\lambda'_2 for every unweighted claw-free graph. The source supplies no resolution.

References

Primary source

Logan Crew and Yongxing Zhang, “e-basis Coefficients of Chromatic Symmetric Functions”, arXiv:2210.03803 (2025).

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