We formally present a first-order logic intended for representing and
reasoning about 2D dynamic multi-agent problem domains. The unique fea
ture of the logic is the uniform use of a Cartesian plane as the basis
for both the spatial and temporal ontology. Our temporal structure ha
s an ever changing present. Relative to each present there is a past a
nd a future. A feature of this temporal structure is its ability to ca
pture when knowledge is added or updated. Copyright (C) 1997 Elsevier
Science Ltd