Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

[Martin Doerr]

Dear Richard,

I'll shorten now:

On 9/14/2018 7:54 PM, Richard Light wrote:



My suggestion is that we define the "has symbolic content" property, 
and then put our energy into agreeing one or more subproperties of 
rdf:value which meet the known recording requirements for cultural 
heritage information.  By doing this, I suggest that we will have 
solved the main problem which confronts implementors who want to 
express CRM in RDF.

Yep, subproperty of rdf:value is not bad.

I think the polymorphism we describe here, well studied in 
object-oriented languages, is in the nature of Appellations. The 
problem for me is, that the the respective KR models have NOT 
THOUGHT of the case that such polymorphisms can occurr. 
Nevertheless, RDFS is tolerant enough to accept the Superproperty 
statement, but not to create a class which is either URI or *inline 
expanded* object.


This polymorphism occurs EXCLUSIVELY for Symbolic Objects with 
symbol sets a certain machine supports. Another reason not to use 
rdfs:value, because it does not give credit to the fact that only 
Symbolic Objects can have such a "value".
I'm afraid you have lost me here. It would be very helpful to me 
(and might encourage others to join in the conversation) if you 
could post one or two concrete examples of what you mean.
OK, in simple words: there are names which have an identity based on 
a certain sequence of characters. There are others, historically 
interesting, which have a phonetic identity, and even that may vary. 
We collaborate with historians, that deal with family names in the 
Aegean area around 1800, which have no standard spelling at all, not 
even a preferred one. The different spelling variants have later 
evolved into distinct family names. But in order to match instances 
in the documents, we need both concepts of identity.
True, but any instance of the name in a document will only take one 
concrete form, not all of them.  (For handwritten sources it may be a 
matter of judgement what that form actually is.)  So you can record 
the form of name it exhibits (as a string), and then assert that it is 
(in your view) an attestation of the generic family name for which you 
have a URI.
This is not true. We do have counterexamples. The name may take multiple 
forms in the same document.


Even my ancestors used "Derr" instead of "Dörr". Since the local 
dialect does not distinguish "e" and "ö", it is unclear if it is a 
spelling variant of the same phonetics or if the "ö" is an 
etymological misinterpretion, because "Dörr" has a linguistic meaning 
and the "e" in "Derr" may have another semantic root, but this is not 
widely accepted.


So, the names that are not identical to a Literal must be represented 
using a URI. That is what I mean by polymorphism. Also, if we want to 
talk about the name itself as a historical fact, we need a distinct 
identity. All these cases are needed but rare for names. 
There are perfectly good reasons for considering names to be worthy of 
study and recording in their own right.  I would argue that this is 
equally true whether the name in question has one, or many, possible 
forms.  So there is always an argument for minting a URI to represent 
the name as a Symbolic Object. Doing this allows you to make 
statements, for example, about its genesis, its meaning, its 
historical distribution, etc., and means you can record specific 
instances of the name as attestations of this Symbolic Object.


However, I would still argue that /instances /of the name should be 
recorded as strings - the actual value found in the resource in question.

Sure. this is another issue. And they can be multiple...

best,

Martin


For texts, it is the opposite. They are more often in files than in 
literals.


On the other side, only Symbolic Objects can "reside" on computers 
and outside. Therefore the "punning" problem does only occur in 
connection to Symbolic Objects. Only these can have a "value" in the 
machine, whereas rdfs:value may be about anything.



Thanks,

Richard

[1] https://www.w3.org/community/openannotation/



Best,

Martin


Best wishes,

Richard


I agree that we may over-think the point. As I mentioned, the 
superproperty statement I propose has no other effect than that I 
can get E41's and labels back by querying P1 only.


Opinions?

Best,

Martin

On 9/12/2018 9:56 AM, Richard Light wrote:


On 11/09/2018 20:02, Martin Doerr wrote:

Dear All,

Firstly, apologies, the RDF was wrong, it was intended to be P1 
is superproperty of rdfs:label.
I'm not sure that this is something we need to state at all, and I 
worry that - if it is included in our RDFS Schema - it may bring 
unwanted side-effects.  Isn't this saying that any instance of 
rdfs:label is to be treated as an instance of P1?  Bear in mind 
that CRM data may co-exist in triple stores in company with other 
RDF data, which may well use rdfs:label for its own purposes.  
This assertion that 'all rdfs:labels are P1 relationships'

Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

[Richard Light]

On 13/09/2018 20:57, Martin Doerr wrote:
> Dear Richard,
>>
>>> What we need, to my opinion, is a property of Symbolic Object we may
>>> call it "has symbolic content" or "has symbolic content inline" or
>>> anything better, which defines that the symbolic content *is
>>> identical to* the Literal, *abstracted *to the "level of symbolic
>>> specificity" that the Literal implies and that conforms to the
>>> identity condition of the Symbolic Object, i.e., characters of a
>>> certain script, or whatever. That would make the meaning of the
>>> "value" unambiguous.
>> Again, I'm in complete agreement with this line of thought.  One
>> decision we should make is whether this property forms part of the
>> generic CRM framework, or if it is to be an implementation-specific
>> property which only appears in our RDF implementation of the CRM.  My
>> instinct is for it to go into the CRM proper: the treatment of
>> Symbolic Object and its subclasses would I think be made clearer by
>> the addition of this property.
> For CRM proper!
OK: perhaps we should start a new issue to address this?
>>
>> It's worth bearing in mind that RDF strings have a built-in mechanism
>> for specifying the language of the string.  This would allow us to
>> express, for example, a place name in multiple languages by simply
>> having one 'has symbolic content' property per language, each with an
>> associated string.
>>
>>> We may need add another property, such as "is contained in" or so
>>> pointing to a URL actually holding an instance of its content, again
>>> abstracted to the "level of symbolic specificity" that the file
>>> instance implies and that conforms to the identity condition of the
>>> Symbolic Object.
>> I think that we would benefit from some use cases which demonstrate
>> the practical need for this property.  My own instinct is that if we
>> are really just recording a string value, then it is overkill to
>> assign it a URL and put it somewhere 
> I made a jump here. This is for things like a (standardized) text of
> Aristotle in a MS Word document, and in a .html file. If I mean the
> text alleged to Aristotle, I obviously do not mean the type face in MS
> Word to belong to Aristotle's text, nor html layout instructions.
> Means, that both contain the precisely the same text, but are
> themselves different, because they are richer in information, which
> are modern renderings. All three, the standardized text of Aristotle,
> the MS Word representation and the html representation are different
> Symbolic Objects, but one is contained in the other two.
I see: thanks. Yes, this would indeed be a different property, and in
fact the URL concerned will not be a 'Linked Data' URL, since it will
address a non-RDF resource.  So that forms a different discussion,
perhaps?  To me, the Word document and HTML page sound like
"attestations" of the Aristotle text (as the Pelagios/Linked Pasts
people would say).  Another example would be a photograph of a plaque
containing a text of interest.  This would also be an attestation; the
difference is that the text in question is not encoded within the
digital resource.

I'm certainly interested in the interface between the Linked Data world
and the digital humanities world of TEI and Word documents and the
like.  Techniques like Open Annotation [1] could well have a useful role
to play here.

>> My suggestion is that we define the "has symbolic content" property,
>> and then put our energy into agreeing one or more subproperties of
>> rdf:value which meet the known recording requirements for cultural
>> heritage information.  By doing this, I suggest that we will have
>> solved the main problem which confronts implementors who want to
>> express CRM in RDF.
> Yep, subproperty of rdf:value is not bad.
>
>>> I think the polymorphism we describe here, well studied in
>>> object-oriented languages, is in the nature of Appellations. The
>>> problem for me is, that the the respective KR models have NOT
>>> THOUGHT of the case that such polymorphisms can occurr.
>>> Nevertheless, RDFS is tolerant enough to accept the Superproperty
>>> statement, but not to create a class which is either URI or *inline
>>> expanded* object.
>>>
>>> This polymorphism occurs EXCLUSIVELY for Symbolic Objects with
>>> symbol sets a certain machine supports. Another reason not to use
>>> rdfs:value, because it does not give credit to the fact that only
>>> Symbolic Objects can have such a "value".
>> I'm afraid you have lost me here. It would be very helpful to me (and
>> might encourage others to join in the conversation) if you could post
>> one or two concrete examples of what you mean.
> OK, in simple words: there are names which have an identity based on a
> certain sequence of characters. There are others, historically
> interesting, which have a phonetic identity, and even that may vary.
> We collaborate with historians, that deal with family names in the
> Aegean area around 1800, which have no standard spelli

Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

[Martin Doerr]

Dear Richard,


On 12/09/2018 14:55, Martin Doerr wrote:

Dear Richard,

I basically agree with your comments. Specifically however, I indeed 
wanted to say that the official definition of rdfs:label makes it 
exactly a subproperty of P1 (or shortcut of it) in any correct use of 
RDFS. If we want to mix RDFS models, we should have an opinion about 
their compatibility. Otherwise, we would have to regard them as 
alternative that cannot be compared with the CRM.
OK: noted.  My concern is simply that we should not include assertions 
which mean that 'CRM RDF' fails to play nicely with other RDF 
frameworks.  I would welcome the thoughts of others on this issue.


I am not happy with adding rdfs:label to instances of Appellation, 
because this would mean it is a name for a name and not the name. I 
would sympathize with George using rdfs:value, if it had the 
respective semantics.

Yes, we're in full agreement on this.

What we need, to my opinion, is a property of Symbolic Object we may 
call it "has symbolic content" or "has symbolic content inline" or 
anything better, which defines that the symbolic content *is 
identical to* the Literal, *abstracted *to the "level of symbolic 
specificity" that the Literal implies and that conforms to the 
identity condition of the Symbolic Object, i.e., characters of a 
certain script, or whatever. That would make the meaning of the 
"value" unambiguous.
Again, I'm in complete agreement with this line of thought.  One 
decision we should make is whether this property forms part of the 
generic CRM framework, or if it is to be an implementation-specific 
property which only appears in our RDF implementation of the CRM.  My 
instinct is for it to go into the CRM proper: the treatment of 
Symbolic Object and its subclasses would I think be made clearer by 
the addition of this property.

For CRM proper!


It's worth bearing in mind that RDF strings have a built-in mechanism 
for specifying the language of the string.  This would allow us to 
express, for example, a place name in multiple languages by simply 
having one 'has symbolic content' property per language, each with an 
associated string.


We may need add another property, such as "is contained in" or so 
pointing to a URL actually holding an instance of its content, again 
abstracted to the "level of symbolic specificity" that the file 
instance implies and that conforms to the identity condition of the 
Symbolic Object.
I think that we would benefit from some use cases which demonstrate 
the practical need for this property.  My own instinct is that if we 
are really just recording a string value, then it is overkill to 
assign it a URL and put it somewhere 
I made a jump here. This is for things like a (standardized) text of 
Aristotle in a MS Word document, and in a .html file. If I mean the text 
alleged to Aristotle, I obviously do not mean the type face in MS Word 
to belong to Aristotle's text, nor html layout instructions. Means, that 
both contain the precisely the same text, but are themselves different, 
because they are richer in information, which are modern renderings. All 
three, the standardized text of Aristotle, the MS Word representation 
and the html representation are different Symbolic Objects, but one is 
contained in the other two.
else. If it's more than just a string value, in what way is it more?  
Is it an instance of some other class, which we should be defining (or 
have already identified)?


My suggestion is that we define the "has symbolic content" property, 
and then put our energy into agreeing one or more subproperties of 
rdf:value which meet the known recording requirements for cultural 
heritage information.  By doing this, I suggest that we will have 
solved the main problem which confronts implementors who want to 
express CRM in RDF.

Yep, subproperty of rdf:value is not bad.


Whereas the shortcut interpretation is attractive, it is not exactly 
the same. Using a shortcut, we say that the intermediate node is of 
different, independent nature from the terminal node. Here, we do not 
say "Appellation" is related to something called "Literal". We say 
"this Appellation IS itself what is in this Literal". That may or may 
not be a reason to reject this interpretation.
True.  At least two respondents in this conversation have said that 
they prefer the fully-worked-out paths.  Let's sort out an initial 
strategy for RDF based on the current CRM; then we can form a view as 
to whether further shortcuts are still required.


We also have to distinguish Appellations and other Symbolic Objects 
which have multiple symbolic forms, i.e. spelling variants, versions 
etc., from those *being one* symbolic form. The rdfs:value has no 
means to express that. I believe we need yet another property "has 
symbolic content variant". In that case, the URI is necessary, to my 
opinion.
There may be a need for such a property; an analogy would be in SKOS, 
which has skos:prefLabel (one per l

Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

[Richard Light]

On 12/09/2018 14:55, Martin Doerr wrote:
> Dear Richard,
>
> I basically agree with your comments. Specifically however, I indeed
> wanted to say that the official definition of rdfs:label makes it
> exactly a subproperty of P1 (or shortcut of it) in any correct use of
> RDFS. If we want to mix RDFS models, we should have an opinion about
> their compatibility. Otherwise, we would have to regard them as
> alternative that cannot be compared with the CRM.
OK: noted.  My concern is simply that we should not include assertions
which mean that 'CRM RDF' fails to play nicely with other RDF
frameworks.  I would welcome the thoughts of others on this issue.

> I am not happy with adding rdfs:label to instances of Appellation,
> because this would mean it is a name for a name and not the name. I
> would sympathize with George using rdfs:value, if it had the
> respective semantics.
Yes, we're in full agreement on this.

> What we need, to my opinion, is a property of Symbolic Object we may
> call it "has symbolic content" or "has symbolic content inline" or
> anything better, which defines that the symbolic content *is identical
> to* the Literal, *abstracted *to the "level of symbolic specificity"
> that the Literal implies and that conforms to the identity condition
> of the Symbolic Object, i.e., characters of a certain script, or
> whatever. That would make the meaning of the "value" unambiguous.
Again, I'm in complete agreement with this line of thought.  One
decision we should make is whether this property forms part of the
generic CRM framework, or if it is to be an implementation-specific
property which only appears in our RDF implementation of the CRM.  My
instinct is for it to go into the CRM proper: the treatment of Symbolic
Object and its subclasses would I think be made clearer by the addition
of this property.

It's worth bearing in mind that RDF strings have a built-in mechanism
for specifying the language of the string.  This would allow us to
express, for example, a place name in multiple languages by simply
having one 'has symbolic content' property per language, each with an
associated string.

> We may need add another property, such as "is contained in" or so
> pointing to a URL actually holding an instance of its content, again
> abstracted to the "level of symbolic specificity" that the file
> instance implies and that conforms to the identity condition of the
> Symbolic Object.
I think that we would benefit from some use cases which demonstrate the
practical need for this property.  My own instinct is that if we are
really just recording a string value, then it is overkill to assign it a
URL and put it somewhere else.  If it's more than just a string value,
in what way is it more?  Is it an instance of some other class, which we
should be defining (or have already identified)?

My suggestion is that we define the "has symbolic content" property, and
then put our energy into agreeing one or more subproperties of rdf:value
which meet the known recording requirements for cultural heritage
information.  By doing this, I suggest that we will have solved the main
problem which confronts implementors who want to express CRM in RDF.

> Whereas the shortcut interpretation is attractive, it is not exactly
> the same. Using a shortcut, we say that the intermediate node is of
> different, independent nature from the terminal node. Here, we do not
> say "Appellation" is related to something called "Literal". We say
> "this Appellation IS itself what is in this Literal". That may or may
> not be a reason to reject this interpretation.
True.  At least two respondents in this conversation have said that they
prefer the fully-worked-out paths.  Let's sort out an initial strategy
for RDF based on the current CRM; then we can form a view as to whether
further shortcuts are still required.

> We also have to distinguish Appellations and other Symbolic Objects
> which have multiple symbolic forms, i.e. spelling variants, versions
> etc., from those *being one* symbolic form. The rdfs:value has no
> means to express that. I believe we need yet another property "has
> symbolic content variant". In that case, the URI is necessary, to my
> opinion.
There may be a need for such a property; an analogy would be in SKOS,
which has skos:prefLabel (one per language) and skos:altLabel.  However,
I wonder if there is value in being able to express, in an open world
situation, that one symbolic form is the "right" one and the others are
variants.  I would welcome some concrete examples to inform our discussion.

>From your explanations, I am getting a mental picture of an Appellation
which has been the subject of much study, where you want to record, in a
condensed way, all the possible forms which that Appellation might
take.  For example, the sort of entry you might find in an encyclopaedia
or a biographical authority.  I think that a more typical scenario might
be where the 'same' name (e.g. the name of a known individua

Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

[Martin Doerr]

Dear Richard,

I basically agree with your comments. Specifically however, I indeed 
wanted to say that the official definition of rdfs:label makes it 
exactly a subproperty of P1 (or shortcut of it) in any correct use of 
RDFS. If we want to mix RDFS models, we should have an opinion about 
their compatibility. Otherwise, we would have to regard them as 
alternative that cannot be compared with the CRM.


I am not happy with adding rdfs:label to instances of Appellation, 
because this would mean it is a name for a name and not the name. I 
would sympathize with George using rdfs:value, if it had the respective 
semantics.


What we need, to my opinion, is a property of Symbolic Object we may 
call it "has symbolic content" or "has symbolic content inline" or 
anything better, which defines that the symbolic content *is identical 
to* the Literal, *abstracted *to the "level of symbolic specificity" 
that the Literal implies and that conforms to the identity condition of 
the Symbolic Object, i.e., characters of a certain script, or whatever. 
That would make the meaning of the "value" unambiguous.


We may need add another property, such as "is contained in" or so 
pointing to a URL actually holding an instance of its content, again 
abstracted to the "level of symbolic specificity" that the file instance 
implies and that conforms to the identity condition of the Symbolic Object.


Whereas the shortcut interpretation is attractive, it is not exactly the 
same. Using a shortcut, we say that the intermediate node is of 
different, independent nature from the terminal node. Here, we do not 
say "Appellation" is related to something called "Literal". We say "this 
Appellation IS itself what is in this Literal". That may or may not be a 
reason to reject this interpretation.


We also have to distinguish Appellations and other Symbolic Objects 
which have multiple symbolic forms, i.e. spelling variants, versions 
etc., from those *being one* symbolic form. The rdfs:value has no means 
to express that. I believe we need yet another property "has symbolic 
content variant". In that case, the URI is necessary, to my opinion.


I think the polymorphism we describe here, well studied in 
object-oriented languages, is in the nature of Appellations. The problem 
for me is, that the the respective KR models have NOT THOUGHT of the 
case that such polymorphisms can occurr. Nevertheless, RDFS is tolerant 
enough to accept the Superproperty statement, but not to create a class 
which is either URI or *inline expanded* object.


This polymorphism occurs EXCLUSIVELY for Symbolic Objects with symbol 
sets a certain machine supports. Another reason not to use rdfs:value, 
because it does not give credit to the fact that only Symbolic Objects 
can have such a "value".


I agree that we may over-think the point. As I mentioned, the 
superproperty statement I propose has no other effect than that I can 
get E41's and labels back by querying P1 only.


Opinions?

Best,

Martin

On 9/12/2018 9:56 AM, Richard Light wrote:


On 11/09/2018 20:02, Martin Doerr wrote:

Dear All,

Firstly, apologies, the RDF was wrong, it was intended to be P1 is 
superproperty of rdfs:label.
I'm not sure that this is something we need to state at all, and I 
worry that - if it is included in our RDFS Schema - it may bring 
unwanted side-effects.  Isn't this saying that any instance of 
rdfs:label is to be treated as an instance of P1?  Bear in mind that 
CRM data may co-exist in triple stores in company with other RDF data, 
which may well use rdfs:label for its own purposes. This assertion 
that 'all rdfs:labels are P1 relationships' would then be applied to 
this other data as well.  This might well result in incorrect/spurious 
results when SPARQL queries are applied to the data.


In general, I suggest that we are ok to define sub-classes/properties 
of standard RDFS types, but we shouldn't define 
super-classes/properties of them.  (I would welcome comments on the 
validity of this suggestion from someone who understands RDF better 
than me.)


Semantically, the range of rdfs:label, when used, is ontologically an 
Appellation in the sense of the CRM.
Agreed (see my reply from yesterday).  The conclusion I draw from this 
is that we can validly say:


E1 rdfs:label "string value" is a shortcut for the path 'E1 CRM 
Entity' 'P1 is identified by' 'E41 Appellation' ...


in exactly the same spirit as the similarly-worded note which we find 
in the definition of P1 itself. (Obviously, by using this shortcut, we 
lose the information that this string value is an Appellation, but 
that's the nature of short-cuts.)


I agree with George, that all RDF nodes should have a human readable 
label. They name the thing, even if it is a technical node.
I would find it confusing to say, labels are not to be queried, only 
to be read, and the "real" names must have a URI,

regardless weather I have more to say about it.

I am really not a fan of punning, we defin

Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

[Richard Light]

On 11/09/2018 20:02, Martin Doerr wrote:
> Dear All,
>
> Firstly, apologies, the RDF was wrong, it was intended to be P1 is
> superproperty of rdfs:label.
I'm not sure that this is something we need to state at all, and I worry
that - if it is included in our RDFS Schema - it may bring unwanted
side-effects.  Isn't this saying that any instance of rdfs:label is to
be treated as an instance of P1?  Bear in mind that CRM data may
co-exist in triple stores in company with other RDF data, which may well
use rdfs:label for its own purposes.  This assertion that 'all
rdfs:labels are P1 relationships' would then be applied to this other
data as well.  This might well result in incorrect/spurious results when
SPARQL queries are applied to the data.

In general, I suggest that we are ok to define sub-classes/properties of
standard RDFS types, but we shouldn't define super-classes/properties of
them.  (I would welcome comments on the validity of this suggestion from
someone who understands RDF better than me.)

> Semantically, the range of rdfs:label, when used, is ontologically an
> Appellation in the sense of the CRM.
Agreed (see my reply from yesterday).  The conclusion I draw from this
is that we can validly say:

E1 rdfs:label "string value" is a shortcut for the path 'E1 CRM Entity'
'P1 is identified by' 'E41 Appellation' ...

in exactly the same spirit as the similarly-worded note which we find in
the definition of P1 itself. (Obviously, by using this shortcut, we lose
the information that this string value is an Appellation, but that's the
nature of short-cuts.)

> I agree with George, that all RDF nodes should have a human readable
> label. They name the thing, even if it is a technical node.
> I would find it confusing to say, labels are not to be queried, only
> to be read, and the "real" names must have a URI,
> regardless weather I have more to say about it.
>
> I am really not a fan of punning, we definitely forbid it in the CRM.
>
> The point with Appellations is that some, the simple ones, can
> directly be represented in the machine, or be outside. The solution to
> assign a URI in all cases, and then a value or label, does not make
> the world easier. It is extremely bad performance. We talk here about
> implementation, not about ontology.
> You get simply a useless explosion of the graph for a purpose of
> theoretic purity.
Agreed. What we need to do is to propose a simple way of expressing
simple Appellations in RDF.  That is why my shortcut definition above
ends with '...': I don't think we have yet decided how to do this.

I've just been looking over the draft document we are trying to write,
and it currently says that a fully-worked-out path will use 'P3 has note
-> E62 string' to express the value of an E41 Appellation.  This (i.e.
the suggestion to use P3) comes from the definition of the superclass
E90 Symbolic Object.  A comment in our draft RDF document questions
whether this is sufficiently precise, since P3 is simply "a container
for all informal descriptions about an object that have not been
expressed in terms of CRM constructs".  I suggest that we need either to
use rdfs:value to hold the string value, or (better) to define a
CRM-specific subproperty of rdfs:value and use that.  (This subproperty
could be part of the published CRM, or it could just form part of the
'RDF implementation' guidelines.)  I don't think that we should use
rdfs:label here.

I don't think we should concern ourselves with URLs in our RDF guidance
document.  Any implementer of our RDF solutions can choose to assign a
URL to represent any node in the structure, but it won't change the
logic of the resulting RDF, or how it responds to SPARQL queries.

>
> Those claiming confusing should be more precise. Has someone looked at
> query benchmarks? Has someone looked at graphical representations of
> RDF graphs. Do they really look better?
>
> So either we either ignore the issue, and write queries that collect
> names either via P1, URI and a value/label, or via a label, because
> this is where names appear in RDF, we make no punning, but our queries
> implement exactly this meaning. So, we are not better, but do as if we
> wouldn't know.
>
> Or, we describe the fact by punning, have one superproperty for all
> cases, which we can query, and stop thereby the discussion if labels
> are allowed or not, and how they relate to appellations. The punning
> comes in, because the range of the superproperty must comprise the
> ranges of the subproperties. We can play a bit more, make the punning
> with a superproperty of P1, and have both P1 and rdfs:label
> subproperties of it, if this is preferred.
> The solution I describe is just a logical representation of the
> situation, not creating a different situation. It just says that names
> can be complex objects or simple literals.
As I said yesterday, I don't see how any punning strategy can make
differently-structured RDF equivalent for the purposes of querying.
Therefore,

Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

[Martin Doerr]

Dear All,

Firstly, apologies, the RDF was wrong, it was intended to be P1 is 
superproperty of rdfs:label.


Semantically, the range of rdfs:label, when used, is ontologically an 
Appellation in the sense of the CRM.


I agree with George, that all RDF nodes should have a human readable 
label. They name the thing, even if it is a technical node.
I would find it confusing to say, labels are not to be queried, only to 
be read, and the "real" names must have a URI,

regardless weather I have more to say about it.

I am really not a fan of punning, we definitely forbid it in the CRM.

The point with Appellations is that some, the simple ones, can directly 
be represented in the machine, or be outside. The solution to assign a 
URI in all cases, and then a value or label, does not make the world 
easier. It is extremely bad performance. We talk here about 
implementation, not about ontology.
You get simply a useless explosion of the graph for a purpose of 
theoretic purity.


Those claiming confusing should be more precise. Has someone looked at 
query benchmarks? Has someone looked at graphical representations of RDF 
graphs. Do they really look better?


So either we either ignore the issue, and write queries that collect 
names either via P1, URI and a value/label, or via a label, because this 
is where names appear in RDF, we make no punning, but our queries 
implement exactly this meaning. So, we are not better, but do as if we 
wouldn't know.


Or, we describe the fact by punning, have one superproperty for all 
cases, which we can query, and stop thereby the discussion if labels are 
allowed or not, and how they relate to appellations. The punning comes 
in, because the range of the superproperty must comprise the ranges of 
the subproperties. We can play a bit more, make the punning with a 
superproperty of P1, and have both P1 and rdfs:label subproperties of 
it, if this is preferred.
The solution I describe is just a logical representation of the 
situation, not creating a different situation. It just says that names 
can be complex objects or simple literals.


The problem is, that the RDF literals do have meaning beyond being 
symbol sequences.


The punning does not introduce the problem. With or without, the queries 
have to cope with names in either form.
This holds similarly for space primitives and large geometry files, for 
short texts and equivalent files etc.


Opinions?

Best

Martin


--
--
 Dr. Martin Doerr  |  Vox:+30(2810)391625|
 Research Director |  Fax:+30(2810)391638|
   |  Email: mar...@ics.forth.gr |
 |
   Center for Cultural Informatics   |
   Information Systems Laboratory|
Institute of Computer Science|
   Foundation for Research and Technology - Hellas (FORTH)   |
 |
   N.Plastira 100, Vassilika Vouton, |
GR70013 Heraklion,Crete,Greece   |
 |
 Web-site: http://www.ics.forth.gr/isl   |
--

Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

[Richard Light]

Hi,

Apologies for being so quiet on this front.

I'm puzzled by Martin's final declaration test: it says the intention is
to see if P1 can be a /superproperty /of rdfs:label, yet the declaration
(and consequent SPARQL query) asserts/tests that it is a /subproperty
/of rdfs:label:

> The next question is, if P1 can be declared superproperty of
> rdfs:label, so that the query for P1 returns everything CRM regards as
> Appellation. It works:
>
> It was tested by altering the cidoc-crm rdfs file, importing it in
> virtuoso and asking for the subproperties of rdfs:label as follows:
>
> 
>
>  is identified by
>
>  идентифицируется посредством
>
>  est identifiée par
>
>  é identificado por
>
>  
>
>   
>
> *  rdf:resource="http://www.w3.org/2000/01/rdf-schema#label
> "
> />*
> 
>
> 
>
> Query (Give me all the subproperties of rdfs:label) :
>
> select * where {
>
> ?p rdfs:subPropertyOf rdfs:label
>
> }
>
> Result from Virtuoso:
>
> p:
>
> http://www.cidoc-crm.org/cidoc-crm/P1_is_identified_by
> 
>
I suspect that in practice this distinction doesn't particularly matter
(though it does make my brain hurt :-)). Presumably the thinking is that
when you search for P1 relationships you will get all the rdfs:label
shortcuts as well?  (And not the other way round ...?)

Anyway, my point is that a single SPARQL expression cannot pick up both
fully-expressed P1's with an E41 on the end, and 'short cut' P1's with
rdfs:label.  This is because the shape of the RDF is different in the
two cases.  So you're going to have to query for both variant patterns
explicitly, and declaring P1 as a sub- or super-property of rdfs:label
isn't going to save you any time or effort.  Doing so might lead to
unwanted consequences, especially if CRM data forms part of a larger RDF
resource.

As regards your proposed short-cuts (and bearing in mind that P1 is
already a short-cut), I don't have strong views on which approach to
take.  I think that your experiments with Virtuoso demonstrate the 'open
world' nature of the RDFS framework; it allows multiple alternative
possibilities.

If we look at the definition of rdfs:label, it says it represents "a
human-readable version of a resource's /name/" (my italics).  As such,
it is certainly semantically close to our P1 property, whose range is an
E41 Appellation.  So that might be an argument for your second option:
using rdfs:label at the point where P1 would otherwise occur.

Like George, I originally liked the idea of using rdfs:value to
represent values (!), but on re-reading their definitions I now tend to
agree with Martin that rdfs:label is a closer fit, semantically, for our
purposes.  rdfs:value may still be useful for representing more complex
values (e.g. those involving values and units), and we may want to
consider deriving some useful CRM-specific subproperties of rdfs:value. 
But that's a discussion for another day ...

Best wishes,

Richard

On 10/09/2018 20:20, George Bruseker wrote:
> Dear all,
>
> I am a fan of the traditional solution:
>
> 1) E1 -> p1 -> E41 
>
> here the encoding all the way down to a value would be rdfs:value
> VALUE because we want to track the actual string used to represent the
> name (separate from the URI of the name)
>
> We use this solution whenever we want to name something about which we
> care for the name (much of the time)
>
> 2) rdfs:label Value
>
> This should be used on all nodes to give a human readable label. This
> is often enough if we don’t study the names used.
>
> Best,
>
> George
>

-- 
*Richard Light*

Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

[Nicola Carboni]

; 
>> Which then makes developers cross, as there are mixed data types in the 
>> array, and the current specification doesn’t allow the string to be 
>> expressed in an object with only @value as a key.
>> 
>>  
>> 
>> Currently that would be the simpler compaction of:
>> 
>>  
>> 
>> {
>> 
>>   “P1_is_identified_by: [
>> 
>>   “uri-as-identifier”
>> 
>>   ]
>> 
>> }
>> 
>>  
>> 
>> Because P1 can only ever have a resource as its object.
>> 
>>  
>> 
>> Or (if you don’t care for the singleton array), the simplest possible form:
>> 
>>  
>> 
>> {
>> 
>>   “P1_is_identified_by”: “uri-as-identifier”
>> 
>> }
>> 
>>  
>> 
>> Rob
>> 
>>  
>> 
>> From: Crm-sig > <mailto:crm-sig-boun...@ics.forth.gr>> on behalf of Detlev Balzer 
>> mailto:d...@balilabs.de>>
>> Date: Tuesday, September 4, 2018 at 12:11 PM
>> To: "crm-sig@ics.forth.gr <mailto:crm-sig@ics.forth.gr>" 
>> mailto:crm-sig@ics.forth.gr>>
>> Subject: Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and 
>> rdfs:label
>> 
>>  
>> 
>> Am 04.09.2018 um 19:19 schrieb Robert Sanderson:
>> 
>> In particular, it makes it difficult in several serializations to 
>> distinguish between the string “http://example.museum.org/data/1 
>> <http://example.museum.org/data/1>” and the resource that has the URI 
>> http://example.museum.org/data/1 <http://example.museum.org/data/1> as its 
>> identifier.
>> 
>>  
>> 
>> Which ones do you mean? All the serializations I've seen make clear 
>> syntactic distinctions between literals and URIs.
>> 
>>  
>> 
>> While I agree that "punning" is bad practice, I don't see why it should 
>> confuse RDF software tools.
>> 
>>  
>> 
>> Detlev
>> 
>>  
>> 
>>  
>> 
>> Am 04.09.2018 um 19:19 schrieb Robert Sanderson:
>> 
>>   
>> 
>> Dear all,
>> 
>>   
>> 
>> Please no!  This is called “punning” (when the same property can be have 
>> both literals and resources as its range) and is widely recognized as a bad 
>> practice in RDF.
>> 
>>   
>> 
>> In particular, it makes it difficult in several serializations to 
>> distinguish between the string “http://example.museum.org/data/1 
>> <http://example.museum.org/data/1>” and the resource that has the URI 
>> http://example.museum.org/data/1 <http://example.museum.org/data/1> as its 
>> identifier.
>> 
>>   
>> 
>> Rob
>> 
>>   
>> 
>>   
>> 
>> *From: *Crm-sig > <mailto:crm-sig-boun...@ics.forth.gr>> on behalf of Martin Doerr 
>> mailto:mar...@ics.forth.gr>>
>> 
>> *Date: *Saturday, September 1, 2018 at 7:41 AM
>> 
>> *To: *crm-sig mailto:Crm-sig@ics.forth.gr>>
>> 
>> *Subject: *[Crm-sig] Issue: Solution for Dualism of E41 Appellation and 
>> rdfs:label
>> 
>>   
>> 
>> Dear All,
>> 
>> Obviously, there are two ways in RDF to express what the CRM regards as an 
>> Appellation: Either using a URI, instance of E41, and then another property 
>> specifying in whatever way the symbolic content (I am not concerned with 
>> this here), *OR *using rdfs:label, which has exactly the meaning of some 
>> forms of Appellation that can be expressed exhaustively as literal.
>> 
>> Interesting enough, there seems to be no existing validation method, that 
>> would exclude any instance of xsd Datatype to be used as range of rdfs:label.
>> 
>> We have made therefor the following tests with Virtuoso, if P1 can have two 
>> ranges, Literal and E41, and if SPARQL gives the expected answers, it does:
>> 
>> *1.**  **Dualism of Appellations*
>> 
>> The purpose of this is to provide an *RDF based technical solution* for 
>> representing and querying a property which can be at the same time Data and 
>> Object type regardless of the fact that it violates the respective 
>> constraints or rules.
>> 
>> Practically we can have three options of representing appellations. By 
>> taking the example of Alexander the Great with supposed URI: 
>> http://example.com/person/alexander_the_great 
>> <http://example.com/person/alexander_the_great> we can do the following:
>> 
>> 1)  Use the “P1 is identified by” property and an inst

Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

[George Bruseker]

Dear all,

I am a fan of the traditional solution:

1) E1 -> p1 -> E41 

here the encoding all the way down to a value would be rdfs:value VALUE because 
we want to track the actual string used to represent the name (separate from 
the URI of the name)

We use this solution whenever we want to name something about which we care for 
the name (much of the time)

2) rdfs:label Value

This should be used on all nodes to give a human readable label. This is often 
enough if we don’t study the names used.

Best,

George

--
Dr. George Bruseker
R & D Engineer

Centre for Cultural Informatics
Institute of Computer Science
Foundation for Research and Technology - Hellas (FORTH)
Science and Technology Park of Crete
Vassilika Vouton, P.O.Box 1385, GR-711 10 Heraklion, Crete, Greece

Tel.: +30 2810 391619   Fax: +30 2810 391638   E-mail: bruse...@ics.forth.gr
URL: http://www.ics.forth.gr/isl

> On Sep 10, 2018, at 5:06 PM, Mark Fichtner  wrote:
> 
> Dear all,
> 
> the main question for me is: Is the use of rdf:label in this case really the 
> intended way by the CIDOC CRM? In fact P1 currently has a valid range and E41 
> is a valid class and not a primitive datatype. Why should we substitute this?
> 
> I agree with Martin that we should integrate old data that has a different 
> model and therefore the proposal and the work is very nice to see. However I 
> think we should have exactly one best practice. At the GNM we typically have 
> regular instances of E41, which in my eyes follows the CIDOC CRM better, so I 
> would love to see this in the best practice.
> 
> Best,
> 
> Mark Fichtner
> 
> 2018-09-04 21:29 GMT+02:00 Robert Sanderson  <mailto:rsander...@getty.edu>>:
> Hi Detlev,
> 
>  
> 
> Apologies, I meant that the pattern makes it more complicated to understand, 
> as opposed to it being ambiguous in the data (which would be much worse!). 
> More difficult for a human rather than for the machine :)
> 
>  
> 
> For example, in JSON-LD, it would result in
> 
>  
> 
> {
> 
>   “P1_is_identified_by”: [
> 
>   “uri-as-string”,
> 
>   {
> 
>  “@id”: “uri-as-identifier”
> 
>   }
> 
>   ]
> 
> }
> 
>  
> 
> Which then makes developers cross, as there are mixed data types in the 
> array, and the current specification doesn’t allow the string to be expressed 
> in an object with only @value as a key.
> 
>  
> 
> Currently that would be the simpler compaction of:
> 
>  
> 
> {
> 
>   “P1_is_identified_by: [
> 
>   “uri-as-identifier”
> 
>   ]
> 
> }
> 
>  
> 
> Because P1 can only ever have a resource as its object.
> 
>  
> 
> Or (if you don’t care for the singleton array), the simplest possible form:
> 
>  
> 
> {
> 
>   “P1_is_identified_by”: “uri-as-identifier”
> 
> }
> 
>  
> 
> Rob
> 
>  
> 
> From: Crm-sig  <mailto:crm-sig-boun...@ics.forth.gr>> on behalf of Detlev Balzer 
> mailto:d...@balilabs.de>>
> Date: Tuesday, September 4, 2018 at 12:11 PM
> To: "crm-sig@ics.forth.gr <mailto:crm-sig@ics.forth.gr>" 
> mailto:crm-sig@ics.forth.gr>>
> Subject: Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and 
> rdfs:label
> 
>  
> 
> Am 04.09.2018 um 19:19 schrieb Robert Sanderson:
> 
> In particular, it makes it difficult in several serializations to distinguish 
> between the string “http://example.museum.org/data/1 
> <http://example.museum.org/data/1>” and the resource that has the URI 
> http://example.museum.org/data/1 <http://example.museum.org/data/1> as its 
> identifier.
> 
>  
> 
> Which ones do you mean? All the serializations I've seen make clear syntactic 
> distinctions between literals and URIs.
> 
>  
> 
> While I agree that "punning" is bad practice, I don't see why it should 
> confuse RDF software tools.
> 
>  
> 
> Detlev
> 
>  
> 
>  
> 
> Am 04.09.2018 um 19:19 schrieb Robert Sanderson:
> 
>   
> 
> Dear all,
> 
>   
> 
> Please no!  This is called “punning” (when the same property can be have both 
> literals and resources as its range) and is widely recognized as a bad 
> practice in RDF.
> 
>   
> 
> In particular, it makes it difficult in several serializations to distinguish 
> between the string “http://example.museum.org/data/1 
> <http://example.museum.org/data/1>” and the resource that has the URI 
> http://example.museum.org/data/1 <http://example.museum.org/data/1> as its 
> identifier.
> 
>   
> 
> Rob
> 
>   
> 
>   
> 
> *From: *

Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

[Mark Fichtner]

Dear all,

the main question for me is: Is the use of rdf:label in this case really
the intended way by the CIDOC CRM? In fact P1 currently has a valid range
and E41 is a valid class and not a primitive datatype. Why should we
substitute this?

I agree with Martin that we should integrate old data that has a different
model and therefore the proposal and the work is very nice to see. However
I think we should have exactly one best practice. At the GNM we typically
have regular instances of E41, which in my eyes follows the CIDOC CRM
better, so I would love to see this in the best practice.

Best,

Mark Fichtner

2018-09-04 21:29 GMT+02:00 Robert Sanderson :

> Hi Detlev,
>
>
>
> Apologies, I meant that the pattern makes it more complicated to
> understand, as opposed to it being ambiguous in the data (which would be
> much worse!). More difficult for a human rather than for the machine :)
>
>
>
> For example, in JSON-LD, it would result in
>
>
>
> {
>
>   “P1_is_identified_by”: [
>
>   “uri-as-string”,
>
>   {
>
>  “@id”: “uri-as-identifier”
>
>   }
>
>   ]
>
> }
>
>
>
> Which then makes developers cross, as there are mixed data types in the
> array, and the current specification doesn’t allow the string to be
> expressed in an object with only @value as a key.
>
>
>
> Currently that would be the simpler compaction of:
>
>
>
> {
>
>   “P1_is_identified_by: [
>
>   “uri-as-identifier”
>
>   ]
>
> }
>
>
>
> Because P1 can only ever have a resource as its object.
>
>
>
> Or (if you don’t care for the singleton array), the simplest possible form:
>
>
>
> {
>
>   “P1_is_identified_by”: “uri-as-identifier”
>
> }
>
>
>
> Rob
>
>
>
> *From: *Crm-sig  on behalf of Detlev Balzer
> 
> *Date: *Tuesday, September 4, 2018 at 12:11 PM
> *To: *"crm-sig@ics.forth.gr" 
> *Subject: *Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation
> and rdfs:label
>
>
>
> Am 04.09.2018 um 19:19 schrieb Robert Sanderson:
>
> In particular, it makes it difficult in several serializations to
> distinguish between the string “http://example.museum.org/data/1” and the
> resource that has the URI http://example.museum.org/data/1 as its
> identifier.
>
>
>
> Which ones do you mean? All the serializations I've seen make clear
> syntactic distinctions between literals and URIs.
>
>
>
> While I agree that "punning" is bad practice, I don't see why it should
> confuse RDF software tools.
>
>
>
> Detlev
>
>
>
>
>
> Am 04.09.2018 um 19:19 schrieb Robert Sanderson:
>
>
>
> Dear all,
>
>
>
> Please no!  This is called “punning” (when the same property can be have
> both literals and resources as its range) and is widely recognized as a bad
> practice in RDF.
>
>
>
> In particular, it makes it difficult in several serializations to
> distinguish between the string “http://example.museum.org/data/1” and the
> resource that has the URI http://example.museum.org/data/1 as its
> identifier.
>
>
>
> Rob
>
>
>
>
>
> *From: *Crm-sig  on behalf of Martin Doerr <
> mar...@ics.forth.gr>
>
> *Date: *Saturday, September 1, 2018 at 7:41 AM
>
> *To: *crm-sig 
>
> *Subject: *[Crm-sig] Issue: Solution for Dualism of E41 Appellation and
> rdfs:label
>
>
>
> Dear All,
>
> Obviously, there are two ways in RDF to express what the CRM regards as an
> Appellation: Either using a URI, instance of E41, and then another property
> specifying in whatever way the symbolic content (I am not concerned with
> this here), *OR *using rdfs:label, which has exactly the meaning of some
> forms of Appellation that can be expressed exhaustively as literal.
>
> Interesting enough, there seems to be no existing validation method, that
> would exclude any instance of xsd Datatype to be used as range of
> rdfs:label.
>
> We have made therefor the following tests with Virtuoso, if P1 can have
> two ranges, Literal and E41, and if SPARQL gives the expected answers, it
> does:
>
> *1.**  **Dualism of Appellations*
>
> The purpose of this is to provide an *RDF based technical solution* for
> representing and querying a property which can be at the same time Data and
> Object type regardless of the fact that it violates the respective
> constraints or rules.
>
> Practically we can have three options of representing appellations. By
> taking the example of Alexander the Great with supposed URI:
> http://example.com/person/alexander_the_great we can do the following:
>
> 1)  Use the “P1 is identified b

Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

[Robert Sanderson]

Hi Detlev,

Apologies, I meant that the pattern makes it more complicated to understand, as 
opposed to it being ambiguous in the data (which would be much worse!). More 
difficult for a human rather than for the machine :)

For example, in JSON-LD, it would result in

{
  “P1_is_identified_by”: [
  “uri-as-string”,
  {
 “@id”: “uri-as-identifier”
  }
  ]
}

Which then makes developers cross, as there are mixed data types in the array, 
and the current specification doesn’t allow the string to be expressed in an 
object with only @value as a key.

Currently that would be the simpler compaction of:

{
  “P1_is_identified_by: [
  “uri-as-identifier”
  ]
}

Because P1 can only ever have a resource as its object.

Or (if you don’t care for the singleton array), the simplest possible form:

{
  “P1_is_identified_by”: “uri-as-identifier”
}

Rob

From: Crm-sig  on behalf of Detlev Balzer 

Date: Tuesday, September 4, 2018 at 12:11 PM
To: "crm-sig@ics.forth.gr" 
Subject: Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and 
rdfs:label

Am 04.09.2018 um 19:19 schrieb Robert Sanderson:
In particular, it makes it difficult in several serializations to distinguish 
between the string “http://example.museum.org/data/1” and the resource that has 
the URI http://example.museum.org/data/1 as its identifier.

Which ones do you mean? All the serializations I've seen make clear syntactic 
distinctions between literals and URIs.

While I agree that "punning" is bad practice, I don't see why it should confuse 
RDF software tools.

Detlev


Am 04.09.2018 um 19:19 schrieb Robert Sanderson:

Dear all,

Please no!  This is called “punning” (when the same property can be have both 
literals and resources as its range) and is widely recognized as a bad practice 
in RDF.

In particular, it makes it difficult in several serializations to distinguish 
between the string “http://example.museum.org/data/1” and the resource that has 
the URI http://example.museum.org/data/1 as its identifier.

Rob


*From: *Crm-sig 
mailto:crm-sig-boun...@ics.forth.gr>> on behalf 
of Martin Doerr mailto:mar...@ics.forth.gr>>
*Date: *Saturday, September 1, 2018 at 7:41 AM
*To: *crm-sig mailto:Crm-sig@ics.forth.gr>>
*Subject: *[Crm-sig] Issue: Solution for Dualism of E41 Appellation and 
rdfs:label

Dear All,
Obviously, there are two ways in RDF to express what the CRM regards as an 
Appellation: Either using a URI, instance of E41, and then another property 
specifying in whatever way the symbolic content (I am not concerned with this 
here), *OR *using rdfs:label, which has exactly the meaning of some forms of 
Appellation that can be expressed exhaustively as literal.
Interesting enough, there seems to be no existing validation method, that would 
exclude any instance of xsd Datatype to be used as range of rdfs:label.
We have made therefor the following tests with Virtuoso, if P1 can have two 
ranges, Literal and E41, and if SPARQL gives the expected answers, it does:
*1.**  **Dualism of Appellations*
The purpose of this is to provide an *RDF based technical solution* for 
representing and querying a property which can be at the same time Data and 
Object type regardless of the fact that it violates the respective constraints 
or rules.
Practically we can have three options of representing appellations. By taking 
the example of Alexander the Great with supposed URI: 
http://example.com/person/alexander_the_great we can do the following:
1)  Use the “P1 is identified by” property and an instance of E41 
Appellation class:

<http://example.com/person/alexander_the_great> 
<http://example.com/person/alexander_the_great>
crm:P1_is_identified_by
<http://example.com/appellation/alexander_the_great> 
<http://example.com/appellation/alexander_the_great> .

<http://example.com/appellation/alexander_the_great> 
<http://example.com/appellation/alexander_the_great>
rdfs:label
"Alexander the Great" .

2)  Use directly the rdfs:label:
<http://example.com/person/alexander_the_great> 
<http://example.com/person/alexander_the_great>
rdfs:label
"Alexander the Great" .

3)  Use the “P1 is identified by” property as a data property (violating 
the rdfs definitions):
<http://example.com/person/alexander_the_great> 
<http://example.com/person/alexander_the_great>
crm:P1_is_identified_by
"Alexander the Great" .

Based on these examples the following steps were followed to test the practical 
application of such cases to a triple store. *Virtuoso triple store* was used 
for the following examples.
1.   The cidoc_crm.rdfs was altered to include the following:

  is identified 
by
 
 


is identified by
 
 http://www.w3.org/2

Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

[Detlev Balzer]

Am 04.09.2018 um 19:19 schrieb Robert Sanderson:
> In particular, it makes it difficult in several serializations to distinguish 
> between the string “http://example.museum.org/data/1” and the resource that 
> has the URI http://example.museum.org/data/1 as its identifier.

Which ones do you mean? All the serializations I've seen make clear syntactic 
distinctions between literals and URIs.

While I agree that "punning" is bad practice, I don't see why it should confuse 
RDF software tools.

Detlev


Am 04.09.2018 um 19:19 schrieb Robert Sanderson:
>  
> 
> Dear all,
> 
>  
> 
> Please no!  This is called “punning” (when the same property can be have both 
> literals and resources as its range) and is widely recognized as a bad 
> practice in RDF.
> 
>  
> 
> In particular, it makes it difficult in several serializations to distinguish 
> between the string “http://example.museum.org/data/1” and the resource that 
> has the URI http://example.museum.org/data/1 as its identifier.
> 
>  
> 
> Rob
> 
>  
> 
>  
> 
> *From: *Crm-sig  on behalf of Martin Doerr 
> 
> *Date: *Saturday, September 1, 2018 at 7:41 AM
> *To: *crm-sig 
> *Subject: *[Crm-sig] Issue: Solution for Dualism of E41 Appellation and 
> rdfs:label
> 
>  
> 
> Dear All,
> 
> Obviously, there are two ways in RDF to express what the CRM regards as an 
> Appellation: Either using a URI, instance of E41, and then another property 
> specifying in whatever way the symbolic content (I am not concerned with this 
> here), *OR *using rdfs:label, which has exactly the meaning of some forms of 
> Appellation that can be expressed exhaustively as literal.
> 
> Interesting enough, there seems to be no existing validation method, that 
> would exclude any instance of xsd Datatype to be used as range of rdfs:label.
> 
> We have made therefor the following tests with Virtuoso, if P1 can have two 
> ranges, Literal and E41, and if SPARQL gives the expected answers, it does:
> 
> 
> *1.**  **Dualism of Appellations*
> 
> The purpose of this is to provide an *RDF based technical solution* for 
> representing and querying a property which can be at the same time Data and 
> Object type regardless of the fact that it violates the respective 
> constraints or rules.
> 
> Practically we can have three options of representing appellations. By taking 
> the example of Alexander the Great with supposed URI: 
> http://example.com/person/alexander_the_great we can do the following:
> 
> 1)  Use the “P1 is identified by” property and an instance of E41 
> Appellation class:
> 
>  
> 
> <http://example.com/person/alexander_the_great> 
> <http://example.com/person/alexander_the_great>
> 
> crm:P1_is_identified_by
> 
> <http://example.com/appellation/alexander_the_great> 
> <http://example.com/appellation/alexander_the_great> .
> 
>  
> 
> <http://example.com/appellation/alexander_the_great> 
> <http://example.com/appellation/alexander_the_great>
> 
> rdfs:label
> 
> "Alexander the Great" .
> 
>  
> 
> 2)  Use directly the rdfs:label:
> 
> <http://example.com/person/alexander_the_great> 
> <http://example.com/person/alexander_the_great>
> 
> rdfs:label
> 
> "Alexander the Great" .
> 
>  
> 
> 3)  Use the “P1 is identified by” property as a data property (violating 
> the rdfs definitions):
> 
> <http://example.com/person/alexander_the_great> 
> <http://example.com/person/alexander_the_great>
> 
> crm:P1_is_identified_by
> 
> "Alexander the Great" .
> 
>  
> 
> Based on these examples the following steps were followed to test the 
> practical application of such cases to a triple store. *Virtuoso triple 
> store* was used for the following examples.
> 
> 1.   The cidoc_crm.rdfs was altered to include the following:
> 
> 
> 
>  is identified 
> by
> 
> 
> 
> 
> 
> 
> 
> 
> 
> is identified by
> 
> 
> 
>  rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"; 
> <http://www.w3.org/2000/01/rdf-schema#Literal>/>
> 
> 
> 
> * *
> 
> So,  an is identified property was added to the initial schema but with 
> rdfs:Literal as a range.
> 
>  
> 
> 2.   The cidoc crm schema was uploaded in virtuoso and the following 
> query (give me the range of P1_is_identified_property) was executed to be 
> sure that the changes have been applied:
&

Re: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

[Robert Sanderson]

Dear all,

Please no!  This is called “punning” (when the same property can be have both 
literals and resources as its range) and is widely recognized as a bad practice 
in RDF.

In particular, it makes it difficult in several serializations to distinguish 
between the string “http://example.museum.org/data/1” and the resource that has 
the URI http://example.museum.org/data/1 as its identifier.

Rob


From: Crm-sig  on behalf of Martin Doerr 

Date: Saturday, September 1, 2018 at 7:41 AM
To: crm-sig 
Subject: [Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

Dear All,

Obviously, there are two ways in RDF to express what the CRM regards as an 
Appellation: Either using a URI, instance of E41, and then another property 
specifying in whatever way the symbolic content (I am not concerned with this 
here), OR using rdfs:label, which has exactly the meaning of some forms of 
Appellation that can be expressed exhaustively as literal.

Interesting enough, there seems to be no existing validation method, that would 
exclude any instance of xsd Datatype to be used as range of rdfs:label.

We have made therefor the following tests with Virtuoso, if P1 can have two 
ranges, Literal and E41, and if SPARQL gives the expected answers, it does:



1.  Dualism of Appellations
The purpose of this is to provide an RDF based technical solution for 
representing and querying a property which can be at the same time Data and 
Object type regardless of the fact that it violates the respective constraints 
or rules.
Practically we can have three options of representing appellations. By taking 
the example of Alexander the Great with supposed URI: 
http://example.com/person/alexander_the_great we can do the following:

1)  Use the “P1 is identified by” property and an instance of E41 
Appellation class:



<http://example.com/person/alexander_the_great><http://example.com/person/alexander_the_great>

crm:P1_is_identified_by

<http://example.com/appellation/alexander_the_great><http://example.com/appellation/alexander_the_great>
 .



<http://example.com/appellation/alexander_the_great><http://example.com/appellation/alexander_the_great>

rdfs:label

"Alexander the Great" .



2)  Use directly the rdfs:label:

<http://example.com/person/alexander_the_great><http://example.com/person/alexander_the_great>

rdfs:label

"Alexander the Great" .



3)  Use the “P1 is identified by” property as a data property (violating 
the rdfs definitions):

<http://example.com/person/alexander_the_great><http://example.com/person/alexander_the_great>

crm:P1_is_identified_by

"Alexander the Great" .


Based on these examples the following steps were followed to test the practical 
application of such cases to a triple store. Virtuoso triple store was used for 
the following examples.

1.   The cidoc_crm.rdfs was altered to include the following:

 is identified 
by




is identified by

http://www.w3.org/2000/01/rdf-schema#Literal";<http://www.w3.org/2000/01/rdf-schema#Literal>/>


So,  an is identified property was added to the initial schema but with 
rdfs:Literal as a range.


2.   The cidoc crm schema was uploaded in virtuoso and the following query 
(give me the range of P1_is_identified_property) was executed to be sure that 
the changes have been applied:



prefix crm: 
<http://www.cidoc-crm.org/cidoc-crm/><http://www.cidoc-crm.org/cidoc-crm/>

prefix rdfs: 
<http://www.w3.org/2000/01/rdf-schema#><http://www.w3.org/2000/01/rdf-schema>



select * where { crm:P1_is_identified_by rdfs:range ?range}



result:
range

http://www.cidoc-crm.org/cidoc-crm/E41_Appellation

http://www.w3.org/2000/01/rdf-schema#Literal




So, it is confirmed that the two ranges have been added. I repeat at this point 
that Virtuoso does not apply any semantic validation. The purpose of this test 
is to prove that this exercise is possible even though conceptually it may not 
be correct.



3.   The ttl data that was presented previously has been added in virtuoso:



@prefix rdfs: 
<http://www.w3.org/2000/01/rdf-schema#><http://www.w3.org/2000/01/rdf-schema> .

@prefix rdf: 
<http://www.w3.org/1999/02/22-rdf-syntax-ns#><http://www.w3.org/1999/02/22-rdf-syntax-ns>
 .

@prefix crm: 
<http://www.cidoc-crm.org/cidoc-crm/><http://www.cidoc-crm.org/cidoc-crm/> .



<http://example.com/person/alexander_the_great><http://example.com/person/alexander_the_great>

crm:P1_is_identified_by 
<http://example.com/appellation/alexander_the_great><http://example.com/appellation/alexander_the_great>
 .



<http://example.com/appellation/alexander_the_great><http://ex

[Crm-sig] Issue: Solution for Dualism of E41 Appellation and rdfs:label

[Martin Doerr]

Dear All,

Obviously, there are two ways in RDF to express what the CRM regards as 
an Appellation: Either using a URI, instance of E41, and then another 
property specifying in whatever way the symbolic content (I am not 
concerned with this here), *OR *using rdfs:label, which has exactly the 
meaning of some forms of Appellation that can be expressed exhaustively 
as literal.


Interesting enough, there seems to be no existing validation method, 
that would exclude any instance of xsd Datatype to be used as range of 
rdfs:label.


We have made therefor the following tests with Virtuoso, if P1 can have 
two ranges, Literal and E41, and if SPARQL gives the expected answers, 
it does:


*1.**Dualism of Appellations*

The purpose of this is to provide an *RDF based technical solution* for 
representing and querying a property which can be at the same time Data 
and Object type regardless of the fact that it violates the respective 
constraints or rules.


Practically we can have three options of representing appellations. By 
taking the example of Alexander the Great with supposed URI: 
http://example.com/person/alexander_the_great we can do the following:


1)Use the “P1 is identified by” property and an instance of E41 
Appellation class:




crm:P1_is_identified_by

 .



rdfs:label

"Alexander the Great" .

2)Use directly the rdfs:label:



rdfs:label

"Alexander the Great" .

3)Use the “P1 is identified by” property as a data property (violating 
the rdfs definitions):




crm:P1_is_identified_by

"Alexander the Great" .

Based on these examples the following steps were followed to test the 
practical application of such cases to a triple store. *Virtuoso triple 
store* was used for the following examples.


1.The cidoc_crm.rdfs was altered to include the following:



is identified by









is identified by



http://www.w3.org/2000/01/rdf-schema#Literal"/>



**

So,an is identified property was added to the initial schema but with 
rdfs:Literal as a range.


2.The cidoc crm schema was uploaded in virtuoso and the following query 
(give me the range of P1_is_identified_property) was executed to be sure 
that the changes have been applied:


prefix crm: 

prefix rdfs: 

select * where { crm:P1_is_identified_by rdfs:range ?range}

*result: *

*range*

http://www.cidoc-crm.org/cidoc-crm/E41_Appellation

http://www.w3.org/2000/01/rdf-schema#Literal

So, it is confirmed that the two ranges have been added. I repeat at 
this point that Virtuoso *does not apply* any semantic validation. The 
purpose of this test is to prove that this exercise is possible even 
though conceptually it may not be correct.


3.The ttl data that was presented previously has been added in virtuoso:

@prefix rdfs:  .

@prefix rdf:  .

@prefix crm:  .



crm:P1_is_identified_by 
 .




rdfs:label "Alexander the Great" .



rdfs:label "Alexander the Great" .



crm:P1_is_identified_by "Alexander the Great" .

4.A query to return all the “identifiers” of alexander the great using 
the is identified property was applied:


prefix crm: 

prefix rdfs: 

select * where

{ crm:P1_is_identified_by 
?identifier }


*result: *

*identifier*

http://example.com/appellation/alexander_the_great

Alexander the Great

So, it is obvious that with the same query both the literal and the uri 
values are returned.


A version of the above query to return also the appellation’s label (but 
not the uri) is the following:


prefix crm: 

prefix rdfs: 

select ?identifier

where {

{crm:P1_is_identified_by 
?identifier }


UNION

{crm:P1_is_identified_by 
?identifier_uri .


?identifier_urirdfs:label ?identifier }

FILTER (!isURI(?identifier))

}

*With the following result :*

*I**dentifier*

Alexander the Great

Alexander the Great

The next question is, if P1 can be declared superproperty of rdfs:label, 
so that the query for P1 returns everything CRM regards as Appellation. 
It works:



It was tested by altering the cidoc-crm rdfs file, importing it in 
virtuoso and asking for the subp