an event in which one participant acts on a second participant, but the change that occurs to the second participant is at least partly independent of the force transmitted by the first participant. Examples: interaction events include pursuit events, events involving two agents such as ordering someone (to do something) or supervising someone, and events involving an agent and an event, state, social institution, and so on, such as managing a budget, avoiding situations, or conforming to institutional standards. (Section 7.3)