  We first introduce a notion of convex structure in generalized metric spaces,
then we introduce tripartite contractions, tripartite semi-contractions,
tripartite coincidence points, as well as tripartite best proximity points for
a given triple $(K;S;T)$ of nonlinear mappings defined on the union $A\cup
B\cup C$ of closed subsets of a generalized metric space. We prove theorems on
the existence and convergence of tripartite coincidence-best proximity points.
