ISO/IEC 24707:2018
(Main)Information technology — Common Logic (CL) — A framework for a family of logic-based languages
Information technology — Common Logic (CL) — A framework for a family of logic-based languages
This document specifies a family of logic languages designed for use in the representation and interchange of information and data among disparate computer systems. The following features are essential to the design of this document. — Languages in the family have declarative semantics. It is possible to understand the meaning of expressions in these languages without appeal to an interpreter for manipulating those expressions. — Languages in the family are logically comprehensive ? at its most general, they provide for the expression of arbitrary first-order logical sentences. — Languages in the family are translatable by a semantics-preserving transformation to a common XML-based syntax, facilitating interchange of information among heterogeneous computer systems. The following are within the scope of this document: — representation of information in ontologies and knowledge bases; — specification of expressions that are the input or output of inference engines; — formal interpretations of the symbols in the language. The following are outside the scope of this document: — specification of proof theory or inference rules; — specification of translators between the notations of heterogeneous computer systems; — computer-based operational methods of providing relationships between symbols in the logical "universe of discourse" and individuals in the "real world". This document describes Common Logic's syntax and semantics. This document defines an abstract syntax and an associated model-theoretic semantics for a specific extension of first-order logic. The intent is that the content of any system using first-order logic can be represented in this document. The purpose is to facilitate interchange of first-order logic-based information between systems. Issues relating to computability using this document (including efficiency, optimization, etc.) are not addressed.
Technologies de l'information — Logique Commune (CL) — Cadre pour une famille des langages logique-basés
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INTERNATIONAL ISO/IEC
STANDARD 24707
Second edition
2018-07
Information technology — Common
Logic (CL) — A framework for a family
of logic-based languages
Technologies de l'information — Logique Commune (CL) — Cadre
pour une famille des langages logique-basés
Reference number
©
ISO/IEC 2018
© ISO/IEC 2018
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ii © ISO/IEC 2018 – All rights reserved
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and abbreviated terms . 4
4.1 Symbols . 4
4.2 Abbreviated terms . 5
5 Requirements and design overview . 5
5.1 Requirements . 5
5.1.1 Common Logic should include full first-order logic with equality . 5
5.1.2 Common Logic should provide a general-purpose syntax for
communicating logical expressions . 5
5.1.3 Common Logic should be easy and natural for use on the Web . 5
5.1.4 Common Logic should support open networks . 6
5.1.5 Common Logic should not make arbitrary assumptions about semantics . 6
5.2 A family of languages . 6
6 Common Logic abstract syntax and semantics . 6
6.1 Common Logic abstract syntax . 6
6.1.1 Abstract syntax categories . 6
6.1.2 Metamodel of the Common Logic abstract syntax . 8
6.1.3 Importation closure .15
6.1.4 Abstract syntactic structure of dialects .16
6.2 Common logic semantics .17
6.3 Datatypes .19
6.4 Satisfaction, validity and entailment .20
6.5 Sequence markers, recursion and argument lists: discussion .20
6.6 Special cases and translations between dialects .21
7 Conformance .21
7.1 Dialect conformance .21
7.1.1 Syntax .21
7.1.2 Semantics .22
7.1.3 Presupposing dialects .23
7.2 Application conformance .24
7.3 Network conformance .24
Annex A (normative) Common Logic Interchange Format (CLIF) .25
Annex B (normative) Conceptual Graph Interchange Format (CGIF) .36
Annex C (normative) eXtended Common Logic Markup Language (XCL) .57
Annex D (informative) Translating between dialects .69
Bibliography .70
© ISO/IEC 2018 – All rights reserved iii
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical
activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work. In the field of information technology, ISO and IEC have established a joint technical committee,
ISO/IEC JTC 1.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/IEC JTC 1, Information technology, SC 32,
Data management and interchange.
This second edition cancels and replaces the first edition (ISO/IEC 24707:2007), which has been
technically revised.
The main changes compared to the previous edition are as follows:
— the list of syntactic errors that have already been identified in the Defect Report has been fixed;
— the XML syntax in Annex C has been corrected and completed;
— a more general approach to annotation of CL-texts has been made;
— semantics has been modified to allow the existence of definitional extensions in CL;
— support for circular imports;
— semantics of CL-module have been clarified;
— clarification of the distinction between segregated and non-segregated dialects;
— clarification of conformance conditions has been made.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO/IEC 2018 – All rights reserved
Introduction
Common Logic is a logic framework intended for information exchange and transmission. The
framework allows for a variety of different syntactic forms, called dialects, all translatable by a
semantics-preserving transformation to a common XML-based syntax.
Common Logic has some novel features, chief among them being a syntax which permits “higher-
order” constructions, such as quantification over classes or relations while preserving a first-order
model theory, and a semantics which allows theories to describe intentional entities such as classes or
properties. It also has provision for the use of datatypes and for naming, importing and transmitting
content on the World Wide Web using XML.
© ISO/IEC 2018 – All rights reserved v
INTERNATIONAL STANDARD ISO/IEC 24707:2018(E)
Information technology — Common Logic (CL) — A
framework for a family of logic-based languages
1 Scope
This document specifies a family of logic languages designed for use in the representation and
interchange of information and data among disparate computer systems.
The following features are essential to the design of this document.
— Languages in the family have declarative semantics. It is possible to understand the meaning of
expressions in these languages without appeal to an interpreter for manipulating those expressions.
— Languages in the family are logically comprehensive – at its most general, they provide for the
expression of arbitrary first-order logical sentences.
— Languages in the family are translatable by a semantics-preserving transformation to a common
XML-based syntax, facilitating interchange of information among heterogeneous computer systems.
The following are within the scope of this document:
— representation of information in ontologies and knowledge bases;
— specification of expressions that are the input or output of inference engines;
— formal interpretations of the symbols in the language.
The following are outside the scope of this document:
— specification of proof theory or inference rules;
— specification of translators between the notations of heterogeneous computer systems;
— computer-based operational methods of providing relationships between symbols in the logical
“universe of discourse” and individuals in the “real world”.
This document describes Common Logic’s syntax and semantics.
This document defines an abstract syntax and an associated model-theoretic semantics for a specific
extension of first-order logic. The intent is that the content of any system using first-order logic can
be represented in this document. The purpose is to facilitate interchange of first-order logic-based
information between systems.
Issues relating to computability using this document (including efficiency, optimization, etc.) are not
addressed.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC 2382:2015, Information technology — Vocabulary
ISO/IEC 10646:2014, Information technology — Universal Coded Character Set (UCS)
ISO/IEC 14977:1996, Information technology — Syntactic metalanguage — Extended BNF
© ISO/IEC 2018 – All rights reserved 1
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