Agents need to communicate in order to accomplish tasks that they
are unable to perform alone. Communication requires agents to share a
common ontology, a strong assumption in open environments where agents
from different backgrounds meet briefly, making it impossible to map
all the ontologies in advance. An agent, when it receives a message,
needs to compare the foreign terms in the message with all the terms in
its own local ontology, searching for the most similar one. However,
the content of a message may be described using an interaction model:
the entities to which the terms refer are correlated with other
entities in the interaction, and they may also have prior probabilities
determined by earlier, similar interactions. Within the context of an
interaction it is possible to predict the set of possible entities a
received message may contain, and it is possible to sacrifice recall
for efficiency by comparing the foreign terms only with the most
probable local ones. This allows a novel form of dynamic ontology
matching.