[sc34wg3] New TMCL slides: at least 2 roles must be played

Patrick Durusau patrick at durusau.net
Tue Nov 24 09:28:21 EST 2009


Steve Newcomb wrote:
> Patrick Durusau wrote:
>> Steve,
>> Steve Newcomb wrote:
>>> Patrick Durusau wrote:
>>>> Steve,
>>>> Steve Newcomb wrote:
>>>>> Lars Marius Garshol wrote:
>>>>>> I can see a need for omissible role types in n-ary relationships 
>>>>>> where it may be the case that one of the role players is not 
>>>>>> known, but in binary relationship then if one of the players is 
>>>>>> not known you can simply omit the entire relationship.
>>>>> I like this rule, but I think it should be more general. Even in 
>>>>> an n-ary association, if there's only one role player, there's no 
>>>>> relationship, so the whole association is otiose. The rule should 
>>>>> be: /At least two roles must be played/.
>>>>> The only thing that bothers me about this rule is that there may 
>>>>> be moments when an association is only partially expressed. But 
>>>>> I'm not sure that it's an issue, really.
>>>> Moments when an association is only partially expressed?
>>>> Hmmm, ok, what about marriage and one role player known but spouse 
>>>> is not? A partial baptism record for example. Not ever going to 
>>>> cure that lack.
>>>> May not know who the other role player is but the existence of the 
>>>> association is not in doubt.
>>>> A subject is lost by omitting the association. That is "a" choice 
>>>> but it isn't one that should be a rule for all topic maps.
>>> "Unknown role player" is very different from "unplayed role".
>>> I would claim that in the example you provide, the role is not 
>>> unplayed. It is played by an unknown person, at least if the 
>>> relationship is known to exist. I guess if there's a baby to be 
>>> baptized, that's evidence enough that a relationship exists, since 
>>> human reproduction takes two to tango.
>> If you want to *define* the subject "association" to consist of at 
>> least two roles, both of which are played but one of the players may 
>> be unknown, I suppose.
>> What puzzles me is why object to an "unplayed role?"
>> Hmmm, ok, say that I play the grandfather role in a grandfather <-> 
>> grandchild association. The later role isn't unknown but in fact 
>> unplayed, at least at this point in time. ;-)
>> Why would you object to my instantiating such an association in my 
>> topic map?
> Because the subject that is represented by an association (TMDM: by a 
> topic that reifies an association) is always a relationship. If fewer 
> than two roleplayers are specified (i.e., if fewer than two subjects 
> are being said to "be related"), then by definition no relationship is 
> being specified. (At least under my own personal understanding of what 
> a "relationship" is.)
> I've heard some comedian or other say, "I'm married to my imaginary 
> lover," while making a crude gesture with one hand. Well, OK, you may 
> say that this particular "marriage" is not a marriage, really, but I 
> would claim that it is nonetheless a relationship, and that 
> relationship is the thing that the crude gesture refers to. Imaginary 
> roleplayers are still roleplayers. The subject of a topic can be 
> anything at all, and a subject that happens to be a relationship can 
> be any relationship at all.
> Actually, though, it's OK with me if a topic map contains an utterance 
> of an association with fewer than two specified roleplayers, because 
> it might be important to allow interchange of incompletely-specified 
> relationships. I'm arguing that, where a Topic Map rhetoric (such as 
> TMDM) provides a subject-proxy expression for /relationships /(such as 
> association information items)/,/ it be explicit that utterances of 
> associations with fewer than two roleplayers are meaningless and 
> should therefore be ignored during subject-centric processing. 
I was with you up to the last sentence. Subject-centric processing does 
not and cannot depend upon some universal notion of subject identity.
> For example, if a topic map has two associations, and neither of them 
> has at least two roleplayers -- they should not be merged, even if 
> they both have the same roles being played (or left unplayed) by the 
> same roleplayer (or absence(s) of roleplayers). 
That sounds like a sensible rule to me because the specification of the 
subject they represent is incomplete, not that they don't represent a 
subject but its specification is incomplete, and therefore I would 
suggest (but not require) that they remain unmerged.

If we go about tossing out *universal* subject-centric processing rules 
topic map users are no better off than the unfortunates who are told 
they must use some ontology because it is more complete, logical, 
precise than their poor, naive, but their own ways to deal with subjects.

Note that I am *not* disagreeing with the notion of subject-centric 
processing but simply that the definition of that processing depends 
solely and proximately upon the specification of that processing by a 
> In Topic Maps, the only reason to merge topics is that they are 
> understood (by someone, presumably for some reason) to represent the 
> same subject. If a topic has no subject, it does not have the same 
> subject as any other topic, even when the other topic is subject-less. 
> It has no subject at all, and so it's not really a topic at all. Where 
> there is no subject, there is no basis for merging, full stop.
Hardly. If the subject has not be specified to the extent that I 
consider sufficient to trigger merging it should not be merged. One such 
case would be incomplete specification of subjects. Another might be 
that there are specifications of subject identity that simply are of no 
interest to me and I don't want to spend the processing cycles on 
merging for those subjects.

Say I were to create a topic map arcade game, that starts with 100 empty 
topics and players must specify 100 topics using various ways to specify 
subjects, it is important that I be able to track the number of "empty" 
or unfilled topics. (Imagine the appropriate number of flashing lights, 
bells, not sure about the "tilt" mechanism, and at the completion of 
each 10 topics the subject identity requirements get harder.) 

Each of those unfilled topics represents an inchoate subject that will 
be known should the player successfully complete it. So, no, I don't 
want it to be "merged" but that isn't at odds with subject-centric 

Actually that game sounds fun. Players would have to remember 
identifiers to invoke merging, etc. Memory plus eye/hand coordination. 
Wonder what that would look like if tied to a news feed so that users 
were actually contributing something useful while playing the game? If 5 
users all "identify" the reference of some word or phrase in a story, it 
bumps up in reliability due to merging of the identifications.

I support "subject-centric computing" but choke on pre-defining what it 
means to have "no subject." Perhaps the freedom to identify any subject 
by implication includes the freedom to decide when there is no subject?

Hope you are looking forward to a great Thanksgiving Holiday! (A US 
custom for which I am baking Challah. First attempt so I have alerted 
the local medical authorities.)


Patrick Durusau
patrick at durusau.net
Chair, V1 - US TAG to JTC 1/SC 34
Convener, JTC 1/SC 34/WG 3 (Topic Maps)
Editor, OpenDocument Format TC (OASIS), Project Editor ISO/IEC 26300
Co-Editor, ISO/IEC 13250-1, 13250-5 (Topic Maps)

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