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Re: drop referentially opaque semantics in embedded triples

From: Peter Patel-Schneider <pfpschneider@gmail.com>
Date: Fri, 07 May 2021 08:52:55 -0400
Message-ID: <40d951331430b69e38a60ae3a33e3f0d657bb88f.camel@gmail.com>
To: thomas l├Ârtsch <tl@rat.io>, public-rdf-star@w3.org
An excellent description of the problems with referential opacity in
embedded triples.   I agree wholeheartedly.  I particularly like the
detailed investigation into the use cases.

I also note that referential opacity works poorly for the annotation
syntax (PG mode).  With referential opacity

:elizabeth :spouse :richard {| :count 2 |} .

does not entail

:elizabeth :spouse :richard {| :count 02 |} .

which I take to be completely unexpected.

(I purposefully picked an example that did not need any external
identity relationship.)

With this observation I would put use cases 3.1, 3.3, 3.4, 3.5, 3.6,
3,8, 3.9, 3.13, and 3.15 decidedly in the referential transparency


PS:  On a technical note, with the new semantics switching between
various versions of transparent and opaque is simply a matter of
changing the triples added when eliminating an embedded triple
(described in Section 6.1).

PPS: On a further technical note, with the new semantics it is possible
to have transparent semantics for some embedded triples and opaque
semantics for other embedded triples - all that is needed is variations
on the syntax that result in different generated triples.  Whether this
is a good idea is a different matter.
Received on Friday, 7 May 2021 12:53:08 UTC

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