English

Trivalent expanders, $(\Delta-Y)$-transformation, and hyperbolic surfaces

Combinatorics 2018-10-15 v1

Abstract

We construct a new family of trivalent expanders tessellating hyperbolic surfaces with large isometry groups. These graphs are obtained from a family of Cayley graphs of nilpotent groups via (ΔY)(\Delta-Y)-transformations. We compare this family with Platonic graphs and their associated hyperbolic surfaces and see that they are generally very different with only one hyperbolic surface in the intersection. Moreover, we study combinatorial, topological and spectral properties of our trivalent graphs and their associated hyperbolic surfaces.

Keywords

Cite

@article{arxiv.1810.05532,
  title  = {Trivalent expanders, $(\Delta-Y)$-transformation, and hyperbolic surfaces},
  author = {Ioannis Ivrissimtzis and Norbert Peyerimhoff and Alina Vdovina},
  journal= {arXiv preprint arXiv:1810.05532},
  year   = {2018}
}

Comments

arXiv admin note: text overlap with arXiv:1202.2304

R2 v1 2026-06-23T04:37:42.331Z