  An IVOA Identifier is a globally unique name for a resource within the
Virtual Observatory. This name can be used to retrieve a unique description of
the resource from an IVOA-compliant registry or to identify an entity like a
dataset or a protocol without dereferencing the identifier. This document
describes the syntax for IVOA Identifiers as well as how they are created. The
syntax has been defined to encourage global-uniqueness naturally and to
maximize the freedom of resource providers to control the character content of
an identifier.
