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Re: After XQuery, are we done?

• To: "Hunsberger, Peter" <Peter.Hunsberger@S...>
• Subject: Re: After XQuery, are we done?
• From: Rick Marshall <rjm@z...>
• Date: Wed, 27 Oct 2004 08:54:41 +1000
• Cc: Elliotte Harold <elharo@m...>, XML Developers List <xml-dev@l...>
• In-reply-to: <1E0CC447E59C974CA5C7160D2A2854EC02FECF3A@S...>
• Organization: Zenucom Pty Ltd
• References: <1E0CC447E59C974CA5C7160D2A2854EC02FECF3A@S...>
• User-agent: Mozilla Thunderbird 0.6 (X11/20040502)

Hunsberger, Peter wrote:

>Elliotte Harold <elharo@m...> writes:
>  
>
>>Hunsberger, Peter wrote:
>>
>>
>>    
>>
>>>Which still leaves the original question; once you've got a way of 
>>>managing and manipulate graphs, why would you need a way to 
>>>distinguish trees?  What does recognizing the special case get you?
>>>      
>>>
>>Because some things are true of trees which are not true of 
>>all graphs, 
>>the algorithms to process them can be made simpler and/or faster. For 
>>instance, you can do a depth first search or breadth first search 
>>without worrying about cycle detection.
>>
>>    
>>
>
>That's exactly my point, if we ever got to the point where we could
>manage graphs (in general) I don't think you'd need to care about trees
>anymore.  Internally, software might optimize the management of all
>kinds of special cases (not just trees), but if we've got Michaels
>non-instance specific network exchange capability then at an interface
>level you shouldn't care anymore?
>
>  
>
the big difference between a graph and a tree is the "root" node. ie a 
tree has a starting point. second big difference, as noted earlier, is 
that trees don't have cycles. this means that trees match easily with 
the way our brains seem to organise information ("The Maths Gene: Why 
Everyone Has It, But Most People Don't Use It  Keith Devlin 
<http://www.amazon.co.uk/exec/obidos/search-handle-url/index=books-uk&field-author=Devlin%2C%20Keith/202-9947616-2794245>") 


try thinking of an alternate way to express a graph using tags, that is 
also easy to read. and looks like a graph. this is a constraint of one 
dimensional respresentation.

rick

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  • RE: After XQuery, are we done?
    • From: "Hunsberger, Peter" <Peter.Hunsberger@S...>

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