Nested Elements and Multiple Inheritance

Hi,

I have a problem, such that i am designing an XML file for a tree 
structure.

For instance later on the tree, the child node happens to be related to 
different sublings. Does that mean i repeatidly define the element tag 
for the child in both the parent siblings or is there a way to define an 
elment once and call it: kind of calling a funtion in a java file.

http://www.cs.wustl.edu/~ravip/facet-docs/facet-thesis.pdf

The link above defines the tree on page 101 of this thesis, i am 
building the XML file for.
You will find the double dependencies for a certain children nodes, how 
do i represent them in an XML document.
Please help me out !

I am attaching an XML document that I currently made, but am stuck on 
thoe multiple dependencies.

Thanks,
Amit Bansal

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=       Amit Bansal          =
= Electrical & Computer Engg.=
=         UCI                =
==============================