FIPA Inform Communicative Act Specification


Document title

FIPA Inform Communicative Act Specification

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Date of this status





Change history


Deprecated by FIPA00037


Line numbering added











2000 Foundation for Intelligent Physical Agents -

Geneva, Switzerland


Use of the technologies described in this specification may infringe patents, copyrights or other intellectual property rights of FIPA Members and non-members. Nothing in this specification should be construed as granting permission to use any of the technologies described. Anyone planning to make use of technology covered by the intellectual property rights of others should first obtain permission from the holder(s) of the rights. FIPA strongly encourages anyone implementing any part of this specification to determine first whether part(s) sought to be implemented are covered by the intellectual property of others, and, if so, to obtain appropriate licenses or other permission from the holder(s) of such intellectual property prior to implementation. This specification is subject to change without notice. Neither FIPA nor any of its Members accept any responsibility whatsoever for damages or liability, direct or consequential, which may result from the use of this specification.


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1 Scope. 1

2 Inform.. 2

3 References. 3

1         Scope

This document specifies the Inform communicative act that is compliant to [FIPA00037] requirements.



2         Inform


The sender informs the receiver that a given proposition is true.


A proposition.


The sending agent:


       holds that some proposition is true,


       intends that the receiving agent also comes to believe that the proposition is true, and,


       does not already believe that the receiver has any knowledge of the truth of the proposition.


The first two properties defined above are straightforward: the sending agent is sincere, and has (somehow) generated the intention that the receiver should know the proposition (perhaps it has been asked). The last property is concerned with the semantic soundness of the act. If an agent knows already that some state of the world holds (that the receiver knows proposition p), it cannot rationally adopt an intention to bring about that state of the world, that is, that the receiver comes to know p as a result of the inform act. Note that the property is not as strong as it perhaps appears.


The sender is not required to establish whether the receiver knows p. It is only the case that, in the case that the sender already happens to know about the state of the receiver's beliefs, it should not adopt an intention to tell the receiver something it already knows.


From the receiver's viewpoint, receiving an inform message entitles it to believe that:


       the sender believes the proposition that is the content of the message, and,


       the sender wishes the receiver to believe that proposition also.


Whether or not the receiver does, indeed, adopt belief in the proposition will be a function of the receiver's trust in the sincerity and reliability of the sender.

Formal Model

<i, inform( j, f )>

FP: Bif Bi( Bifjf Uifjf)

RE: Bjf


Agent i informs agent j that (it is true that) it is raining today.



:sender i

:receiver j


"weather (today, raining)"

:language Prolog)

3         References

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