...Interpretation
This work was partially supported by MURST 60 and by the Italian National Research Council (CNR), project ``Pianificazione Automatica''.
...problem.
 In most cases, a sentence can be ambiguous, so that an a-priori categorization assumes, at best, a default character. Even ``Where is the library?" can be asked just to decide whether it is better to go there to borrow a book, or to find a friend and ask him to lend it to you.
...Try-execute.
The structure of problem solving actions is standard (preconditions, constraints, effects, decompositions). Note only that we include also a specialization hierarchy (represented in the figure by thick arcs) and a decomposition hierarchy (represented by the boxes). The parameter s (that appears in Try-execute beside the agent a and the action act) specifies who is the actual beneficiary of the action, who in many cases can bound to the agent herself. More details are given in [Ardissono & Sestero1996] and [Ardissono, Boella, & Lesmo1995]).
...requested.
Notify-impossible …accounts for dialogues such as ``Can you pass me the salt?" ``Sorry, we have no salt".
...Satisfy).
As in case of ``Can you pass me the salt?" ``Do you see where is it?", assuming that ``Know(agt1,loc(obj))" is a precondition of the domain action ``Pass(agt1,obj,agt2)".
...executed).
[Traum & Allen1994] criticize the approach to plan recognition based on a pure recognition of intentions: they point out that, in many ordinary interactions, the collaboration among agents can be explained by assuming that they are adhering to social obligations, more than working at a common higher level goal.

Although the idea of obligations is reasonable, we do not think it is in contrast with our approach.

In particular, nothing prevents from having plans addressing conventional obligations, whose decomposition can specify how the related obligations can be met in the reply.

Guido Boella Dottorando
Wed Oct 23 08:43:04 MET 1996