XML Namespaces (jmenné prostory)

XML Namespaces (W3C Recommendation, currently Namespaces in XML 1.0 (Third Edition) W3C Recommendation 8 Dec 2009): http://www.w3.org/TR/REC-xml-names

to new XML, there exists Namespaces in XML 1.1 W3C Recommendation (Second Edition) 16 August 2006. Andrew Layman, Richard Tobin, Tim Bray, Dave Hollander

They define logical spaces for names of elements, attributes in XML document.

They give the elements and attributes the "third dimension".

To each NS in XML, there is exactly one ("globally") unique identifier, given by URI (URIs is a superset of URLs).

NS corresponding to an URI does not anyhow relate to content that would potentially be available under the URL ("nothing is downloaded when processing NSs".