Xsv displays the error message shown fig

	pythonhtp1_15.fm Page 509 Saturday, December 15, 2001 2:12 PM
	Chapter 15	Extensible Markup Language (XML)

The Schema in Fig. 15.12 indicates that every book element must contain child ele-ment title. If this element is omitted, the document is well formed, but not valid. If we remove line 8 from Fig. 15.11, XSV displays the error message shown in Fig. 15.13.

15.7 XML Vocabularies

	XML allows document authors to create their own tags to describe data precisely. People
	and organizations in various fields of study have created many different XML vocabularies
	for structuring data. Some of these vocabularies are: MathML (Mathematical Markup Lan-
	guage), Scalable Vector Graphics (SVG), Wireless Markup Language (WML), Extensible
	Business Reporting Language (XBRL), Extensible User Interface Language (XUL) and
	VoiceXML™. Two other examples of XML vocabularies are W3C XML Schema and the
	Fig. 15.13 XML document that does not conform to a W3C XML Schema.

	510	Extensible Markup Language (XML)	Chapter 15

Extensible Stylesheet Language (XSL), which is introduced in Section 15.8. The following subsections describe MathML, Chemical Markup Language (CML) and other XML vocab-ularies.

MathML markup describes mathematical expressions for display. Figure 15.14 uses MathML to mark up a simple expression. [Note: In this section, we provide sample outputs that illustrate how a MathML-enabled application might render the markup.]

	1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
	Fig. 15.14 Expression marked up with MathML. (Part 1 of 2.)