English

A counter-example to persistence in generalised preferential attachment trees

Probability 2026-04-17 v1 Combinatorics

Abstract

Consider a generalised preferential attachment tree with attachment function ff, that is a random tree, where at each time-step a node connects to an existing node vv with probability proportional to f(deg(v))f(\mathrm{deg}(v)), where deg(v)\mathrm{deg}(v) denotes the degree of the node in the existing tree. We provide a counter-example to a conjecture of the author asserting that under the assumption j=11f(j)2<\sum_{j=1}^{\infty} \frac{1}{f(j)^2} < \infty there is a persistent hub in the model, that is, a single node that has the maximal degree for all but finitely many time-steps. The counter-example is a minor modification of a related counter-example due to Galganov and Ilienko.

Keywords

Cite

@article{arxiv.2604.15007,
  title  = {A counter-example to persistence in generalised preferential attachment trees},
  author = {Tejas Iyer},
  journal= {arXiv preprint arXiv:2604.15007},
  year   = {2026}
}
R2 v1 2026-07-01T12:12:39.502Z