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Cycle Power Graph


A cycle power graph C_n^r is the rth graph power of the cycle graph C_n (Louis 2017). Thus, two vertices are adjacent in C_n^r exactly when their graph distance in C_n is at most r. Equivalently, C_n^r is the circulant graph Ci_n(1,2,...,min(r,|_n/2_|)).

For 1<=r<|_n/2_|, the cycle power graph C_n^r is a regular graph of degree 2r and has nr edges. For r>=|_n/2_|, it is the complete graph K_n.

Some standard graph families occur as cycle power graphs as follows.

Vasilev (2026, Theorem 1) proved that for integers n>=3, 1<=k<=n, and 1<=r<n, the maximum number of edges in a k-vertex vertex-induced subgraph of C_n^r is attained by any set of k consecutive vertices of the underlying cycle. For fixed r>=4 and sufficiently large n, Makai et al. (2025, Lemmas 10 and 11) independently obtained the same consecutive-vertex extremal conclusion under more restrictive hypotheses. Writing e(G) for the number of edges in a graph G, Vasilev's theorem gives

 max_(U subset= V(C_n^r); |U|=k)e(C_n^r[U])={(k; 2)   for r>=|_n/2_|; e(P_k^r)   for r<|_n/2_| and k<=n-r; e(P_k^r)+(k-n+r+1; 2)   for r<|_n/2_| and k>n-r ,
(1)

where P_k^r is the rth power of the path graph P_k and

 e(P_k^r)={(k; 2)   for k<=r+1; rk-(r+1; 2)   for k>r+1 .
(2)

Vasilev's extremal result also gives the Cheeger constant h(C_n^r)=r(r+1)/|_n/2_| for 1<=r<|_n/2_|. The n-antiprism graph is the special case C_(2n)^2, so its Cheeger constant is 6/n for n>=3. For r>=|_n/2_|, C_n^r is a complete graph, whose Cheeger constant is [n/2].

The consecutive vertex sets need not be the only maximizers. For example, label the vertices of the underlying cycle graph C_6 as 1, 2, ..., 6 in cyclic order. The vertices numbered 1, 3, and 5 then form a triangle in C_6^2, so this nonconsecutive vertex set also induces the maximum of three edges. A classification of all maximizing vertex sets remains open (Vasilev 2026).


See also

Antiprism Graph, Cheeger Constant, Circulant Graph, Cocktail Party Graph, Complete Graph, Cycle Graph, Graph Power, Path Graph

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References

Louis, J. "Spanning Trees in Directed Circulant Graphs and Cycle Power Graphs." Monatshefte Math. 182, 51-63, 2017. https://doi.org/10.1007/s00605-016-0912-2.Makai, T.; Pasch, M.; Petrova, K.; and Schiller, L. "Sharp Thresholds for Higher Powers of Hamilton Cycles in Random Graphs." 20 Feb 2025. https://arxiv.org/abs/2502.14515.Vasilev, K. "The Edge-Isoperimetric Inequality for Powers of Cycles." Mathematics and Education in Mathematics 55, 78-84, 2026. https://doi.org/10.55630/mem.2026.55.078-084.

Cite this as:

Weisstein, Eric W. "Cycle Power Graph." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/CyclePowerGraph.html

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