Views

The problem
Suppose we have a paragraph that contains the following words:  A B C D E F G H I J K L

Then suppose we want to group each of the sentences as follows:

 ( A B C D ) ( E F G H ) ( I J K L )

Okay. So now we got the sentences in. Now suppose we want to group line groups as follows:  ( A B { C D ) ( E F } { G H ) ( I J } K L )

Well, thats looks nice on the wiki, but this is an example of overlapping hierarchies, which is difficult to encode into XML since the following is invalid ( using &lt;s&gt; for sentence ) :  &lt;s&gt;A B&lt;lg&gt;C D&lt;/s&gt;&lt;s&gt;E F&lt;/lg&gt;&lt;lg&gt;G H&lt;/s&gt;&lt;s&gt;I J&lt;/lg&gt;K L&lt;/s&gt;