Asymptotic corank growth conjecture for chromatic roots

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For a finite graph GG, let π(G,z)\pi(G,z) be its chromatic polynomial and define

ρ(G)=max⁡{∣z−1∣:π(G,z)=0}.\rho(G)=\max\{|z-1|:\pi(G,z)=0\}.

Let ρk\rho_k be the maximum of ρ(G)\rho(G) over graphs of corank kk.

Asymptotic corank-growth conjecture. As k→∞k\to\infty,

ρk=[1+o(1)]klog⁡k.\rho_k=\left[1+o(1)\right]\frac{k}{\log k}.

This is presented as an expected consequence of the corrected fixed-corank extremal conjecture. The paper establishes matching lower bounds of this order from generalized theta graphs and an upper bound ρk≤k\rho_k\leq k, but does not determine the asymptotic growth exactly.

References

Primary source

Jason Brown, Carl Hickman, Alan D. Sokal and David G. Wagner, “On the chromatic roots of generalized theta graphs”, arXiv:math/0012033 (2000).

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