The Hosoya Index is calculated by summing the number of matchings for all possible subgraphs of a given molecular graph. For a molecule represented as a graph \( G \), the Hosoya Index \( Z(G) \) can be defined as:
Z(G) = Σ m_k(G)
where \( m_k(G) \) is the number of k-matchings in the graph G. This calculation can be complex for larger molecules, but there are computational tools available to perform these calculations efficiently.
