Markup encodes a description of the document's storage layout and logical structure.
XML provides a mechanism to impose constraints on the storage layout and logical structure.
characters with both precomposed and base diacritic forms) match only if they have the same representation in both strings. (Of strings and rules in the grammar:) A string matches a grammatical production if it belongs to the language generated by that production.
(Of content and content models:) An element matches its declaration when it conforms in the fashion described in the constraint [VC: Element Valid].] [Definition: Marks a sentence describing a non-binding recommendation included to increase the chances that XML documents can be processed by the existing installed base of SGML processors which predate the Web SGML Adaptations Annex to ISO 8879.] [Definition: A data object is an XML document if it is well-formed, as defined in this specification.
W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent.[Definition: A software module called an XML processor is used to read XML documents and provide access to their content and structure.] [Definition: It is assumed that an XML processor is doing its work on behalf of another module, called the application.] This specification describes the required behavior of an XML processor in terms of how it must read XML data and the information it must provide to the application.XML was developed by an XML Working Group (originally known as the SGML Editorial Review Board) formed under the auspices of the World Wide Web Consortium (W3C) in 1996.XML is an application profile or restricted form of SGML, the Standard Generalized Markup Language [ISO 8879].By construction, XML documents are conforming SGML documents.For the convenience of readers, an XHTML version with color-coded revision indicators is also provided; this version highlights each change due to an erratum published in the errata list for the previous edition, together with a link to the particular erratum in that list.