Doubt about name space declaration block

Citing from:   http://www.w3.org/TR/owl-guide/


I get the following namespace declaration:

<rdf:RDF
     xmlns     ="http://www.w3.org/TR/2004/REC-owl-guide-20040210/wine#"
     xmlns:vin ="http://www.w3.org/TR/2004/REC-owl-guide-20040210/wine#"
     xml:base  ="http://www.w3.org/TR/2004/REC-owl-guide-20040210/wine#"
     xmlns:food="http://www.w3.org/TR/2004/REC-owl-guide-20040210/food#"
     xmlns:owl ="http://www.w3.org/2002/07/owl#"
     xmlns:rdf ="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
     xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
     xmlns:xsd ="http://www.w3.org/2001/XMLSchema#">

Later in the document internal references are like this:

<owl:Class rdf:ID="Pasta">
   <rdfs:subClassOf rdf:resource="#EdibleThing" />
   ...
</owl:Class>

xml:base  ="http://www.w3.org/TR/2004/REC-owl-guide-20040210/wine#"
Why do we have the "#" character ath the end of basename ? Isn't it a 
duplicate ?

best,
Andrea Splendiani