English

Removing induced powers of cycles from a graph via fewest edits

Combinatorics 2023-07-27 v1

Abstract

What is the minimum proportion of edges which must be added to or removed from a graph of density pp to eliminate all induced cycles of length hh? The maximum of this quantity over all graphs of density pp is measured by the edit distance function, edForb(Ch)(p)\text{ed}_{\text{Forb}(C_h)}(p), a function which provides a natural metric between graphs and hereditary properties. Martin determined edForb(Ch)(p)\text{ed}_{\text{Forb}(C_h)}(p) for all p[0,1]p \in [0,1] when h{3,,9}h \in \{3, \ldots, 9\} and determined edForb(C10)(p)\text{ed}_{\text{Forb}(C_{10})}(p) for p[1/7,1]p \in [1/7, 1]. Peck determined edForb(Ch)(p)\text{ed}_{\text{Forb}(C_h)}(p) for all p[0,1]p \in [0,1] for odd cycles, and for p[1/h/3,1]p \in [ 1/\lceil h/3 \rceil, 1] for even cycles. In this paper, we fully determine the edit distance function for C10C_{10} and C12C_{12}. Furthermore, we improve on the result of Peck for even cycles, by determining edForb(Ch)(p)\text{ed}_{\text{Forb}(C_h)}(p) for all p[p0,1/h/3]p \in [p_0, 1/\lceil h/3 \rceil ], where p0c/h2p_0 \leq c/h^2 for a constant cc. More generally, if ChtC_h^t is the tt-th power of the cycle ChC_h, we determine edForb(Cht)(p)\text{ed}_{\text{Forb}(C_h^t)}(p) for all pp0p \geq p_0 in the case when (t+1)h(t+1) \mid h, thus improving on earlier work of Berikkyzy, Martin and Peck.

Keywords

Cite

@article{arxiv.2307.14260,
  title  = {Removing induced powers of cycles from a graph via fewest edits},
  author = {Amarja Kathapurkar and Richard Mycroft},
  journal= {arXiv preprint arXiv:2307.14260},
  year   = {2023}
}

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17 pages