Document title:

Abstract Content Representation Work Plan

Document number:


Document source:

(see authors below)

Document status:


Date of this status:


Change history:


Initial Draft


Minor adjustment, renamed to ACR


Submitted to FAB


FAB comments (see end)


Francis G. McCabe



Problem Statement:  FIPA specifications permit arbitrary content languages – so long as they contain the notion of a proposition and term. In practice, many content languages are somewhat similar, being based on versions of either first order logic or a modal logic.


On the other hand, typical platform services require a multitude of different lower level representations in order to facilitate interoperation; for example XML, RMI serialization, S-expression notations.


FIPA specifications control the precise syntax and semantics of ACL expressions; however it would be beneficial for platform providers as well as agent developers to make is easier to build encoders and decoders for content language expressions.


The purpose of this work plan is to develop an abstract content representation that will acts as an intermediate syntactic layer between content languages and other agent platform services.


Objective: There are five main objectives of this work-plan:

1.       Review the precise requirements of an abstract content representation

2.       Develop a specification of an abstract content representation. It is expected that the core form of the specification will be a set of UML diagrams and specifications.

3.       Identify and specify the mapping from several of the content languages in FIPA’s content language library into the ACR

4.       Identify and specify standard mappings from the ACR into concrete representations such as XML and/or textual S-expression notation.

5.       Identify any requirements for standard encoding services for encoding and decoding ACR expressions.


Technology:  Developing abstract syntaxes is a standard technique for compiler writers.


Functionality: The Abstract Content Representation specification should indicate:

·         The representation of variables, constants, composite terms, propositions, quantifies propositions, connective formulae (including modal connectives).

·         The standard mapping for the SL family of FIPA content languages.

·         The standard encodings of abstract content language expressions into common encoded forms.


Specifications generated: A specification of an abstract content representation language


Plan for Work and Milestones: The plan is for a 7 month program of work and includes the following steps:

·         2001/07 Initiation within a FIPA TC

·         2001/10 First draft of abstract content language specification

·         2002/01 Experimental version of specification published


The project plan will be reviewed and revised, if and when necessary.



·         [FIPA00001] FIPA Abstract Architecture Specification

·         [FIPA00007] FIPA Content library specification

·         [FIPA00037] FIPA Communicative Act Library Specification

·         [FIPA00061] FIPA Agent communication language specification

·         This work should be coordinated with any Ontology work active within FIPA



·         Francis G. McCabe (Fujitsu Laboratories)

·         Fabio Bellifemine (CSELT)

·         Steve Willmott (EPFL)


FAB Comments:

This work plan has been approved and has been assigned to the Architecture Technical Committee.