The top-level type in the representation is the parameterized
action (see Figure 
); we call it ``parameterized''
because an action depends on its participants (agent and objects) for
the details of how it to be accomplished. For instance, opening a door
and opening a window will involve very different behaviors on the part
of the agent. The subparts of a parameterized action can refer to
particular aspects of the agent and objects as part of their meaning. In
the sections that follow, we specify and discuss each subpart of the
representation.
Figure: The parameterized action type