Abstract
Let G be a graph. The irregularity index of G, denoted by t(G), is the number of distinct values in the degree sequence of G. For any graph G, t(G) ≤ Δ(G), where Δ(G) is the maximum degree. If t(G) = Δ(G), then G is called maximally irregular. In this paper, we give a tight upper bound on the size of maximally irregular graphs, and prove the conjecture proposed in [6] on the size of maximally irregular triangle-free graphs. Extremal graphs are also characterized.
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This research is supported by NSFC (61222201,11171283) and SRFDP (20126501110001).
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Liu, F., Zhang, Z. & Meng, J. The Size of Maximally Irregular Graphs and Maximally Irregular Triangle-Free Graphs. Graphs and Combinatorics 30, 699–705 (2014). https://doi.org/10.1007/s00373-013-1304-1
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DOI: https://doi.org/10.1007/s00373-013-1304-1