xml名称空间

Question

<?xml version="1.0" encoding="gb2312"?>
<books:books xmlns:people="http://www.xgj.com/people"  xmlns:books="http://www.xgj.com/books">
<books:book>
<books:title>JSP 深入编程</books:title>
<books:author>
 <people:name>张三</people:name>
 <people:title>作家</people:title>
</books:author>
</books:book>
</books:books>
这个代码里面的 <books:books xmlns:people="http://www.xgj.com/people"  xmlns:books="http://www.xgj.com/books">里的books:books我认为要不要都可以,但是不清楚这里写出来是什么意思,大家帮一下