Johnson graph

A Johnson graph, denoted as \( J(n, k) \), is a type of vertex-transitive graph that represents the relationships between the \( k \)-element subsets of an \( n \)-element set. Specifically, the vertices of a Johnson graph are the \( k \)-element subsets of a set with \( n \) elements, and there is an edge between two vertices (subsets) if their intersection has exactly \( k-1 \) elements.