A clique in a undirected graph \(G = V,E\) is a subset V’ ⊆ V of vertices, such that
1
If (u, v) ∈ E then u ∈ V’ and v ∈ V’
2
If (u, v) ∈ E then u ∈ V’ or v ∈ V’
3
Each pair of vertices in V’ is connected by an edge
4
All pairs of vertices in V’ are not connected by an edge