Test statistic 10: Is metabolite m exchanged by cell i (that belongs to cell type t) and other spatially proximal cells (that belong to cell type u)?

In an analogous way to the equation defined in Test statistic 9, the equation below represents the individual cell/spot metabolite (or ligand-receptor pathway) values when cell type identity is considered:

\[ H_{i \in C_t}^{t,u} (m) = \sum_{a,b \in m}^{} H_{i \in C_t}^{t,u} (ab) \]

This equation is only used for visualization purposes, and no statistical test has been implemented.