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Re: Model theory, abstract syntax

From: pat hayes <phayes@ai.uwf.edu>
Date: Mon, 23 Jul 2001 19:10:26 -0700
Message-Id: <v04210113b782887e5596@[130.107.66.237]>
To: Graham Klyne <Graham.Klyne@Baltimore.com>
Cc: w3c-rdfcore-wg@w3.org
>At 09:08 PM 7/16/01 +0100, I wrote:
>>At 01:56 PM 7/16/01 -0500, Aaron Swartz wrote:
>>>I'm unclear on the difference between model theory and abstract 
>>>syntax. Can someone clarify?
>>
>>I'll take a shot;  I guess the real formal systems folks will put me right...
>>
>>I think they are clearly different, but related, issues.
>>
>>- Abstract syntax defines a language (i.e. a set of well formed 
>>formulae, or wff) in terms of some set of terminal symbols.  Given 
>>a formula, it allows us to say whether or not it is a well formed 
>>sentence (instance) of the language.  It also provides us with an 
>>annotation for the the structure of a wff that can be used as a 
>>reference point for defining semantics for the various allowed 
>>forms.  In summary:  abstract syntax is primarily about forms.
>
>On reflection, that's not quite right...  I think it's closer to say 
>that an abstract syntax captures the essential forms of a language, 
>without necessarily providing detailed rules for recognition of 
>wffs.  This group has decided to use N-triples as the basis for its 
>abstract syntax, in which case it does define a specific form of 
>wff, but I don't think this is necessarily true of all abstract 
>syntax.
>
>Although I've often heard the term used, and think I have a feel for 
>what it means, I don't believe I've ever seen a specific definition 
>of "abstract syntax".

The term is due to John McCarthy who introduced it 
http://www-formal.stanford.edu/jmc/towards/towards.html  in the 
context of giving semantics for programming languages. It is widely 
used in theoretical CS. See 
http://www-formal.stanford.edu/jmc/towards/node12.html for a very 
brief intro.

Pat

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Received on Monday, 23 July 2001 22:10:20 EDT

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