Let C7 denote the cycle graph on 7 vertices.
We define C9 to be the Shannon capacity of C7:
C9:=Θ(C7),
where for a graph G, the Shannon capacity Θ(G) is defined by
Θ(G):=n≥1supα(G⊠n)1/n.
Here α(H) denotes the independence number of a graph H, and ⊠
is the strong graph product.