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 I'informationLogique Commune (CL)-Cadre pourunefamilledes langages logique-bases Referencenumber IEC IS0/IEC24707:2018(E) iso @IS0/IEC2018 IS0/IEC24707:2018(E) COPYRIGHTPROTECTEDDOCUMENT @IS0/IEC2018 All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either IsO at the address below orIso's memberbody in the countryof the requester. ISO copyright office CP 401 : Ch. de Blandonnet 8 CH-1214 Vernier,Geneva Phone:+41227490111 Fax:+41 22 749 09 47 Email: [email protected] Website: www.iso.org Published in Switzerland ii @ IS0/IEC 2018 -All rights reserved IS0/IEC24707:2018(E) Contents Page Foreword ..iv Introduction.. ..V 1 Scope. 2 Normative references .... 3 Terms and definitions ..2 4 Symbols andabbreviatedterms 4.1 Symbols .4 4.2 Abbreviatedterms .5 5 Requirements anddesign overview .5 5.1 Requirements .5 5.1.1 Common Logic should include full first-order logic with equality 5.1.2 Common Logic should provide a general-purpose syntax for communicatinglogicalexpressions ..5 5.1.3 Common Logic should be easy and natural for use on the Web .5 5.1.4 Common Logic should supportopen 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 Abstractsyntaxcategories .6 6.1.2 Metamodel of the Common Logic abstract syntax. ..8 6.1.3 Importation closure. .15 6.1.4 Abstractsyntacticstructureofdialects ..16 6.2 Common logic semantics. ..17 6.3 Datatypes .19 6.4 Satisfaction,validityand 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 Dialectconformance 21 7.1.1 Syntax 21 7.1.2 Semantics 22 7.1.3 Presupposing dialects 23 7.2 Application conformance. 24 7.3 Networkconformance .24 AnnexA (normative)Common Logic InterchangeFormat (CLIF) ..25 Annex B (normative) Conceptual Graph Interchange Format (CGIF) ..36 Annex C (normative) eXtended Common Logic Markup Language (XCL) ..57 AnnexD(informative)Translatingbetweendialects ..69 Bibliography ..70 @ IS0/IEC 2018 - All rights reserved iii