[sc34wg3] to advance Topic Maps

[Sam Hunting]

I think the discussion under this subejct line has diverged from
substantive matters, and so I would like to bring it back.


[steve newcomb]
> In order to advance Topic Maps, it is urgent that we align the SAM
> with the requirements for TM Applications prescribed in the TMM.  In
> order to do that:

Note the word "urgent."


> (1) The SAM should be expressed and constrained in such a way that it
>     is clear that the SAM can be extended, and that its extensions can
>     extend the rules for merging and number of relationship types that
>     can determine the subjects of their role players.
> 
>     Currently, the SAM makes no provision for such extensions.  The
>     SAM provides no general doctrine for merging, in terms of which it
>     explains both its own merging rules, and those that may be added
>     by TM Applications that include (inherit) and extend the SAM.
> 
>     Specifically, the SAM does not say how (or even whether) the
>     instances of user-defined association types can determine or
>     influence whether their role players should merge.

So, if there's a sense of urgency, this should be disclosed ASAP. Yes?

> (2) The SAM should be expressed and constrained in such a way that it
>     is clear that topic maps that are based on the SAM can be merged
>     rigorously and predictably, not only with each other, but also
>     with topic maps that are not based on the SAM.
> 
>     The current SAM makes no provision for this.  

So, if there's a sense of urgency, this should be rectified ASAP. Yes?

>     The TMM shows how the SAM can be expressed in such a way as to
>     allow other TM Applications, including but not limited to TM
>     Applications that inherit (or "include") the SAM, to be
>     independently designed and maintained without sacrificing the
>     integrity of the topic maps that are based on them when SAM and
>     non-SAM topic maps are merged.  
> 
>     It's important to maintain the integrity of knowledge even after
>     it is merged with other knowledge.  The TMM is designed to meet
>     the requirement of preserving the integrity of merged topic maps.
> 
>     Any data models that we publish for Topic Maps should be informed
>     by sensible doctrines that establish the general rubric under
>     which diverse merging rules must co-operate, despite the diversity
>     of the knowledge domains and world-views from which they emanate.
>     The TMM proposes such a rubric.
> 
> (3) The SAM should be expressed and constrained in such a way that it
>     is clear that the SAM reflects the WG3's intentions regarding
>     which subjects it reifies (which subjects are capable of being
>     role players and are subject to merging), vs. which subjects are
>     not reifiable in systems that are governed only by the SAM.
> 
>     The current SAM document does not clarify this.  In the absence of
>     such clarification, there is no basis for any claims we (or
>     anybody else) might make about the integrity with which knowledge
>     is handled, even under the SAM's own rules.  

So, if there's a sense of urgency, this should be rectified ASAP. Yes?

> The TMM requires all
>     TM Applications to make explicit the limits of their support for
>     the SLUO, and that their behaviors be deterministic and
>     predictable, even in multi-source, multi-TM-Application
>     environments.  (The "Subject Location Uniqueness Objective (SLUO)"
>     is the principle that all topics that have the same subject should
>     be merged.)  The support of every TM Application for the SLUO is
>     necessarily limited.  It's important that users are able to know
>     exactly how the SLUO is met by any TM Application(s) they use.

So, if there's a sense of urgency, this should be disclosed ASAP. Yes?

>     The SAM, as currently written, doesn't state the limits of its
>     support for the SLUO.  At least one of the things that the SAM
>     does needs an especially detailed disclosure: the SAM allows the
>     reification of subjects to be controlled, not by the inherent
>     logic of the SAM, but rather by syntactic constructs that are used
>     in a given interchangeable instance.  This makes the merging
>     responsibilities of implementations ambiguous.  It becomes
>     impossible, in the general case, to preserve the integrity of
>     topic maps across merging operations with other topic maps,
>     because if a subject is reified in one topic map, and unreified in
>     another, the two topic maps cannot be merged into a single topic
>     map that preserves the integrity of both originals.  If we decide
>     that the SAM really should be designed in such a way that its
>     implementations are exempted from respecting the SLUO in this way,
>     then we must disclose the fact, and we must say exactly how all
>     SAM implementations will uniformly resolve all the ensuing
>     ambiguities.  Again, the TMM doesn't care how much or how little a
>     TM Application respects the SLUO; it merely demands that the
>     limits be disclosed.

So, if there's a sense of urgency, this should be disclosed ASAP. Yes?


> In N0393, there's a checklist of things that need to be done when
> defining a TM Application such as the SAM:
> http://www.isotopicmaps.org/tmmm/TMMM-latest.html#parid0781.  There's
> also a checklist for Syntax Deserialization Definitions, such as for
> XTM and HyTM:
> http://www.isotopicmaps.org/tmmm/TMMM-latest.html#parid0775.

So, if there's a sense of urgency, these checklists should be evaluated
ASAP. Yes? (How hard can this be?)

> It's possible to reconcile the SAM and the TMM.  I hope we will all
> read the new SAM document (which is looking cleaner than ever -
> http://www.isotopicmaps.org/sam/sam-model/), and the new TMM document,
> too, with that goal.

Since the TMM (Topic Maps Model) is designed to support TMAs (Topic Map
Applications) like the SAM, and not to replace it or compete with it,
this should not be too hard to do....

Sam Hunting
eTopicality, Inc.

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