2020/09/09 by B. G. Oh, Oh, Byung-Geun, Byung-Geun Oh
Mathematics · Computer Science · #Graph theory and applications #Limits and Structures in Graph Theory #Advanced Graph Theory Research
paper · pdf · doi:10.48550/arxiv.2009.04394
We provide sharp bounds for the isoperimetric constants of infinite plane\ngraphs (tessellations) with bounded vertex and face degrees. For example, if\nG is a plane graph satisfying the inequalities p1 \≤ deg v \≤\np2 for v \∈ V(G) and q1 \≤ deg f \≤ q2 for f \∈ F(G),\nwhere p1, p2, q1, and q2 are natural numbers such that 1/pi + 1/qi\n\≤ 1/2, i=1,2, then we show that \
Phi (p1, q1)
leq
infS\n
frac|
partial S||V(S)|
leq
Phi (p2, q2), where the infimum is taken\nover all finite nonempty subgraphs S \⊂ G, \∂ S is the set of\nedges connecting S to G \∖ S, and \Φ(p,q) is defined by \
Phi\n(p, q) = (p-2)
sqrt1 -
frac4(p-2)(q-2). For p1=3 this gives an\naffirmative answer to a conjecture by Lawrencenko, Plummer, and Zha from 2002,\nand for general pi and qi our result fully resolves a question posed in\nthe book by Lyons and Peres from 2016, where they extended the conjecture of\nLawrencenko et al. to the above form.\n