English

Extremizing antiregular graphs by modifying total $\sigma$-irregularity

Combinatorics 2024-11-05 v1

Abstract

The total σ\sigma-irregularity is given by σt(G)={u,v}V(G)(dG(u)dG(v))2, \sigma_t(G) = \sum_{\{u,v\} \subseteq V(G)} \left(d_G(u) - d_G(v)\right)^2, where dG(z)d_G(z) indicates the degree of a vertex zz within the graph GG. It is known that the graphs maximizing σt\sigma_{t}-irregularity are split graphs with only a few distinct degrees. Since one might typically expect that graphs with as many distinct degrees as possible achieve maximum irregularity measures, we modify this invariant to \IR(G)={u,v}V(G)dG(u)dG(v)f(n), \IR(G)= \sum_{\{u,v\} \subseteq V(G)} |d_G(u)-d_G(v)|^{f(n)}, where n=V(G)n=|V(G)| and f(n)>0f(n)>0. We study under what conditions the above modification obtains its maximum for antiregular graphs. We consider general graphs, trees, and chemical graphs, and accompany our results with a few problems and conjectures.

Keywords

Cite

@article{arxiv.2411.01530,
  title  = {Extremizing antiregular graphs by modifying total $\sigma$-irregularity},
  author = {Martin Knor and Riste Škrekovski and Slobodan Filipovski and Darko Dimitrov},
  journal= {arXiv preprint arXiv:2411.01530},
  year   = {2024}
}

Comments

10 pages, 1 figure

R2 v1 2026-06-28T19:46:25.346Z