FIPA Not Understood Communicative Act Specification


Document title

FIPA Not Understood Communicative Act Specification

Document number


Document source


Document status


Date of this status





Change history


Deprecated by FIPA00037


Line numbering added










2000 Foundation for Intelligent Physical Agents -

Geneva, Switzerland


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1 Scope. 3

2 Not Understood. 3

3 References. 3

1         Scope

This document specifies the Not Understood communicative act that is compliant to [FIPA00037] requirements.


2         Not Understood


The sender of the act (for example, i) informs the receiver (for example, j) that it perceived that j performed some action, but that i did not understand what j just did. A particular common case is that i tells j that i did not understand the message that j has just sent to i.


A tuple consisting of an action or event, for example, a communicative act, and an explanatory reason.


The sender received a communicative act that it did not understand. There may be several reasons for this: the agent may not have been designed to process a certain act or class of acts, or it may have been expecting a different message. For example, it may have been strictly following a pre-defined protocol, in which the possible message sequences are predetermined. The not-understood message indicates to that the sender of the original (misunderstood) action that nothing has been done as a result of the message.


This act may also be used in the general case for i to inform j that it has not understood js action. The second term of the content tuple is a proposition representing the reason for the failure to understand.


Note: It is not possible to fully capture the intended semantics of an action not being understood by another agent. The characterization below captures that an event happened and that the recipient of the not-understood message was the agent of that event. Additionally, because it is possible that f (the reason for failure) is not a well-formed formula, f cannot be part of the semantic characterization.

Formal Model

<i, not-understood(j, a, f)>

<i, Inform( j, a >

FP: BiaBi (Bifja Uifja)

RE: Bja




a = f ($x) Bi ((ie Done(e) Agent(e, j) Bj(Done(e) Agent(e, j)

(a = e))) = x).


Agent i did not understand a query-if message (see [FIPA00053]) because it did not recognize the ontology.



:sender i

:receiver j



:sender j

:receiver i )

(unknown (ontology www)))

:language FIPA-SL)

3         References

[FIPA00037] FIPA Communicative Act Library Specification. Foundation for Intelligent Physical Agents, 2000.

[FIPA00053] FIPA Query If Communicative Act Specification. Foundation for Intelligent Physical Agents, 2000.