Mobile UNITY refers to a notation system and proof logic initially designed
to accommodate the special needs of the emerging Żeld of mobile computing. The
model allows one to deŻne units of computation and mobility and the formal
rules for coordination among them in a highly decoupled manner. In this paper,
we reexamine the expressive power of the Mobile UNITY coordination constructs
from a new perspective rooted in the notion that disciplined usage of a power-
ful formal model must rely on formally deŻned schemas. Several coordination
schemas are introduced and formalized. They examine the relationship between
Mobile UNITY and other computing models and illustrate the mechanics of em-
ploying Mobile UNITY as the basis for a formal semantic characterization of
coordination models.