XCLX: An XML-based Common Logic eXtension with Embedded Geography Markup Language Mary E. Athan September 2011 A dissertation submitted in partial fulfillment of the requirements of the Masters Degree in Geographic Information Systems of the University of Leeds Abstract A novel eXtensible Markup Language (XML)-based Common Logic eXtension, called XCLX, is presented. The novel syntax draws from the standard syntaxes Common Logic Interchange Format (CLIF) and eXtended Common Logic Markup Language (XCL), as well as Rule Markup Language (RuleML), Interoperable Knowledge representation Language (IKL), IKRIS Context Language (ICL), and XML Inclusions (XInclude). In addition, the syntax is open to user extensions, including embedding elements from foreign namespaces as names, functions and atomic sentences, and has a meta-language for self-extensibility. These features allow Common Logic to embed structured data, such as Geography Markup Language (GML), while maintaining a well-defined semantics. The overall syntax is defined by a modular schema, using a design pattern developed for RuleML. The XCLX semantics is defined either by formal mappings into equivalent syntactic forms (in XCLX or foreign dialects, including CLIF, IKL, ICL), or axiomatically through the meta-language. The semantics of the meta-language is novel and is stated directly. A number of illustrative examples, drawn from geography and GML, are presented. ii Appendix 1: Declaration of Academic Integrity SCHOOL OF GEOGRAPHY UNIVERSITY OF LEEDS DECLARATION OF ACADEMIC INTEGRITY This form must be completed, signed and attached to every dissertation submitted for a degree in Geography at the University of Leeds. I have read the University regulations on cheating and plagiarism and I confirm that this piece of work is my own and does not include any unacknowledged work from any other sources. I understand that the title of this dissertation and my name, as its author, may be included in an on-line catalogue of School of Geography dissertations. Also, that the mark/grade may be recorded on the dissertation when it is stored in the School of Geography. I agree to this. Signed................................................................................. Date.................................2011-09-11 Surname Athan First names Mary Programme of Study Postgraduate MA MSc X Masters Programme Title Geographic Information Systems Other (give programme title) Dissertation title XCLX: An XML-based Common Logic eXtension with Embedded Geography Markup Language Dissertation tutor: Word length* Oliver Duke-Williams 14845 * Word length - exclude bibliography, appendix, tables, diagrams iii Acknowledgments I wish to thank RuleML, Inc. for partial support of the work presented in this dissertation, and Harold Boley for many fruitful discussions, the Common Logic community, including John Sowa, Chris Menzel and Pat Hayes, for help in understanding the Common Logic and IKL specifications, Bill Andersen for use of the Common Logic Sourceforge repository, my adviser Oliver Duke-Williams for advice in the preparation of the dissertation, my parents for their unwavering support, my children Penelope and Helen, for understanding, and my husband, Jason, for being always by my side, as you will always be in my heart. iv Table of Contents Chapter 1 Introduction........................................................................................................1 Section 1.1 Background and Motivation.........................................................................1 Illustration 1: Tree diagram of Lisp equivalent of y = x + 1..........................................1 Illustration 2: Tree diagram of the MathML equivalent to y = x + 1.............................3 Section 1.2 Goals............................................................................................................9 Section 1.3 Objectives.....................................................................................................9 Section 1.4 RoadMap....................................................................................................10 Chapter 2 Literature Review.............................................................................................12 Section 2.1 Syntax.........................................................................................................12 CL Abstract Syntax.............................................................................................13 Grammars for the Lisp-style Syntaxes...............................................................13 RuleML Syntax...................................................................................................13 GML Syntax: Conceptual Models......................................................................13 Comparison of Syntax in Structured Data and KR languages............................13 Section 2.2 Semantics...................................................................................................14 CL Semantics......................................................................................................14 Semantics of IKL................................................................................................16 Semantics of GML..............................................................................................16 Semantics of GML Application Schemas...........................................................16 Comparison of the Semantics of Structured Data and KR Languages...............16 Chapter 3 Specifications of XCLX...................................................................................18 Section 3.1 Encoding and Tokenization........................................................................18 3.1.a XCLX Encoding and Tokenization Specifications..........................................18 Section 3.2 Names.........................................................................................................18 Names in the CL Abstract Specifications...........................................................19 Names in CLIF...................................................................................................20 Names in IKL Syntax..........................................................................................21 Names in XCL1..................................................................................................21 Names in XML...................................................................................................23 URIs, IRIs and Relative References..............................................................23 Datatypes........................................................................................................23 Qualified Names, IRIs and CURIEs..............................................................24 Names in RuleML...............................................................................................26 Names in GML...................................................................................................26 3.2.a XCLX Name Specifications............................................................................27 Section 3.3 Terms..........................................................................................................28 3.3.a XCLX Term Specifications.............................................................................28 Section 3.4 Term Sequences..........................................................................................29 3.4.a XCLX Term Sequence and Sequence Marker Specifications.........................29 Section 3.5 Equations....................................................................................................29 3.5.a XCLX Equation Specifications.......................................................................30 Section 3.6 Atomic Sentences.......................................................................................30 3.6.a XCLX Atomic Sentence Specifications...........................................................31 Section 3.7 Boolean Sentences.....................................................................................31 3.7.a XCLX Boolean Sentence Specifications.........................................................31 Section 3.8 Quantification.............................................................................................31 3.8.a XCLX Quantification Specifications...............................................................32 Section 3.9 Context.......................................................................................................32 v CL Modules........................................................................................................33 Context in IKL....................................................................................................34 Context in ICL....................................................................................................35 Context in RuleML.............................................................................................35 Context in GML..................................................................................................35 3.9.a XCLX Context Specifications.........................................................................36 Section 3.10 Phrases and Texts.....................................................................................36 Phrases and Texts in the CL Dialects..................................................................36 Phrases