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So far, I have found out that chordal graphs have linear number of maximal cliques with respect to the number of vertices. In general case, it is exponential.

I am trying to determine whether the number of maximal cliques in a $(2C_4, C_5,P_5)$-free graph is linear or polynomial with respect to the number of vertices.

In a $(2C_4, C_5,P_5)$-free graph, the largest induced cycle is of length 4, and no two 4-cycles are edge-disjoint.

Is there a paper that mentions such result?

JimN
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padawan
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1 Answers1

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(Answered also on https://cstheory.stackexchange.com/questions/47691/)

A ($2C_4$, $C_5$, $P_5$)-free graph may have exponentially many maximal cliques. For example, the complement of the disjoint union of $n/3$ triangles with $3^{n/3}$ maximal cliques is $K_1 \cup K_2$-free, and thus has none of $2C_4$, $C_5$, $P_5$ appear as an induced subgraph. https://doi.org/10.1007/BF02760024

Note: If the complement of a graph has $k$ pairwise independent edges, then they give you $2^k$ maximal cliques. Conversely, it is known that the number of maximal cliques is upper-bounded by a function of the maximum number of independent edges in the complement . https://onlinelibrary.wiley.com/doi/abs/10.1002/net.3230230308

padawan
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Yota Otachi
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