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Regarding a question on the mailing list www-ql

From: Murali Mani <mani@CS.UCLA.EDU>
Date: Mon, 19 Mar 2001 18:01:42 -0800 (PST)
To: <www-xml-query-comments@w3.org>
Message-ID: <Pine.SOL.4.33.0103191753580.6505-100000@panther.cs.ucla.edu>

One more mail for the day.
This mail concerns the question archived at
A portion of the mail is given below:

In XQuery, is "list" always synonmyous with "ordered forest"? Are the
in an ordered forest considered siblings (having the same parent) of the
same tree?

I see the term "ordered forest" used for both the entire input data model
instance, as well as what's returned by individual path expressions. At
first, I thought this was an overloaded use of the term, because in the
first case, all the documents and document fragments are indeed siblings
(children of the "implicit root node determined by the environment"),
whereas in the second case, the returned nodes are not necessarily
at all (particularly when selecting attributes or using the UNION
But maybe I shouldn't consider an ordered forest as being one tree
containing child siblings in either case?

In order not to overload the term forest, I would like you to consider the
term "hedge". Hedge is a sequence of trees -- "a hedge is to a tree what a
string is to character".

If you would like to use hedge, please let me know because I am trying to
keep track of the awareness of the research community of this term.

Also regarding types, please consider using tree types and hedge types --
a tree type is a type whose value is a tree (it can be specified as a
union of tree types), a hedge type is a type whose value is a hedge
(specified as a model group over tree types and hedge types).

cheers and regards - murali.
Received on Monday, 19 March 2001 21:01:59 UTC

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