Linear Euler-characteristic bound for nonnegative-curvature vertices in polyhedral maps

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Let GG be a simple polyhedral map on a surface M\mathbb{M} with Euler characteristic χ(M)≤0\chi(\mathbb{M})\le 0. For each vertex vv, let F(v)F(v) be the set of incident faces and define its combinatorial curvature by

Φ(v)=1−deg⁡(v)2+∑α∈F(v)1deg⁡(α).\Phi(v)=1-\frac{\operatorname{deg}(v)}{2}+\sum_{\alpha\in F(v)}\frac{1}{\operatorname{deg}(\alpha)}.

The conjecture. For each surface M\mathbb{M}, there exists a constant cMc_{\mathbb{M}} such that, if

∣V(G)∣>cM∣χ(M)∣,|V(G)|>c_{\mathbb{M}}|\chi(\mathbb{M})|,

then GG contains a vertex vv with Φ(v)≥0\Phi(v)\ge 0.

This is presented as an expected consequence for polyhedral maps on a fixed surface. The supplied text gives no resolution or further supporting result, so its status remains open.

References

Primary source

Ryuzo Torii, “Local structures in polyhedral maps on surfaces, and path transferability of graphs”, arXiv:0904.4012 (2009).

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