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Re: [higgins-dev] Two bug fixes toHOWL(higgins.owl)[nonbreakingchange] 
Paul,
1. Of course, there is a posibility on HOWL level for SimpleValue to have Attributes. But I and Valery assume that simple value shlould not have Attributes (and I suppose Jim thinks so, because now ISimpleValue interface doesn't extend IHasAttributes). Simple value should be really simple. Otherwise, ISimpleValue interface should extend IHasAttributes interface. 

2.


> The higgins:Attribute is a holder of metadata for a set of
higgins:Values.
There is one problem related to metadata of attribute. We need to describe which kinds of metadata can attibute have. We do it setting appropriate class - holder of metadata as domain of appropriate metadata property. If we assume that each attribute should have some default metadata set (higgins:validFrom, higgins:lastModified etc.), these metadata properties should have hggins:Attribute class as domain. Then, suppose, we create simple attribute with type higgins:name (higgins:name is subproperty of higgins:attribute). There is two possible cases:
a) we do not need any additional type of metadata for this new attribute. As a result we can use higgins:Attribute to hold metatada of this attribute.
b) we need to define additional metadata for this attribute. As result we should create new class - holder of metadata for this attribute (suppose higgins:NameAttribute, that is subclass of higgins:Attribute).
The question is - should we always create new subclass of higgins:Attribute for each new subproperty of higgins:attribute (even if this attribute does not require new metadata types)? I prefer to always create new subclass of higgins:Attribute. 

Thanks,
Sergey Lyakhov
----- Original Message ----- From: "Paul Trevithick" <paul@xxxxxxxxxxxxxxxxx> To: "'Higgins (Trust Framework) Project developer discussions'" <higgins-dev@xxxxxxxxxxx> 
Sent: Saturday, May 26, 2007 1:07 AM
Subject: RE: [higgins-dev] Two bug fixes toHOWL(higgins.owl)[nonbreakingchange] 





Sergei wrote:


> Both ComplexValue and SimpleValue are sub-classes of Value. By stating
the
> range as Value we allow both possibilities.

Of course, they both are sub-classes of Value. But SimpleValue can not
have
attributes (at least ISimpleValue interface doesn't extend IHasAttributes, 
because there is no any sence for SimpleValue to have attributes).


Let's start over here. You originally wrote:
  1. SimpleValue can not contain attributes (only ComplexValue can), so
  it will be more correct to allow the range of higgins:attribute to be
  ComplexValue, not Value.
In addition to cases where the range might be a ComplexValue, I can imagine 
a higgins:attribute sub-property that has a range of SimpleValue. Here's
one: eyeColor. An instance of eyeColor would have a domain of <some DS> and 
a range of higgins:String. (A higgins:String is a subclass of
higgins:SimpleValue). Thus I maintain that since a higgins:attribute's range might be a ComplexValue and it might be a SimpleValue, then to allow either 
one, it should be specified as Value, the superclass of both.



Also I have one question about metadata: let's suppose that we have
attribute with 2 values and one metadata container (higgins:Attribute) as
it
was in your example. The question is - what should we do with metadata
when
both values were removed from attribute? Should we delete metadata when
we
remove last value of attribute?


Yes, I think what you propose is the correct convention.



Thanks,
Sergey Lyakhov

----- Original Message -----
From: "Paul Trevithick" <paul@xxxxxxxxxxxxxxxxx>
To: "'Higgins (Trust Framework) Project developer discussions'"
<higgins-dev@xxxxxxxxxxx>
Sent: Friday, May 25, 2007 8:08 PM
Subject: RE: [higgins-dev] Two bug fixes to HOWL
(higgins.owl)[nonbreakingchange]


>
> SergeyL wrote:
>>
>> Paul,
>>
>> > 2) bug fix: allowed the range of higgins:attribute to be either
>> > higgins:Value (as it was) or higgins:Attribute (new--this object is
the
>> > holder of metadata about the entire set of values (i.e. "ranges") of
a
>> set
>> > of higgins:attributes
>>
>> 1. SimpleValue can not contain attributes (only ComplexValue can), so
it
>> will be more correct to allow the range of higgins:attribute to be
>> ComplexValue, not Value.
>
> Both ComplexValue and SimpleValue are sub-classes of Value. By stating
the
> range as Value we allow both possibilities.
>
>>
>> 2. Really higgins:attribute is a property of DS (or complex value) >> that 
>> contains higgins:Value (simple or complex). What sence is there for
>> higgins:Attribute class to be the range of  higgins:attribute? Do you
>> mean
>> that we should use the same property to store as values of attribute >> as 
>> metadata of this attribute?
>
> All will become more clear as I work on some examples. But here is > where 
> I'm
> headed...
>
> The higgins:Attribute is a holder of metadata for a set of
higgins:Values.
>
> Here is an example of its use: Consider foo:eyeColor to be a property > of 
a
> DS (a sub-property of higgins:attribute property). Imagine three
instances
> of this eyeColor property: two of them point to higgins:Values (e.g. > two 
> higgins:Strings having associated literal values of "blue" and "green"
> respectively), and the third points to a higgins:Attribute that holds
> metadata about the set of Values. As a trivial example, this
> higgins:Attribute could hold the metadata property "numberOfValues" and
> have
> a range/value of "2".
>
> Thus the metadata (numberOfValues = 2) is bound to the values
> ("blue","green") as follows:
>  * the relevant ObjectProperty instances (all three of them) have the
same
> URI (in our example, "foo:eyeColor)
>  * we follow a convention that there is at most one higgins:Attribute
> instance for a given higgins:attribute sub-property
>
> -Paul
>
>>
>> Thanks,
>> Sergey Lyakhov
>>
>> ----- Original Message -----
>> From: "Paul Trevithick" <paul@xxxxxxxxxxxxxxxxx>
>> To: "'Higgins (Trust Framework) Project developer discussions'"
>> <higgins-dev@xxxxxxxxxxx>
>> Sent: Friday, May 25, 2007 6:01 PM
>> Subject: [higgins-dev] Two bug fixes to HOWL (higgins.owl) [non
>> breakingchange]
>>
>>
>> > 1) bug fix: allowed the domain of higgins:attribute to be either
>> > DigitalSubject (as it was) or ContextObject (new)
>> >
>> > 2) bug fix: allowed the range of higgins:attribute to be either
>> > higgins:Value (as it was) or higgins:Attribute (new--this object is
the
>> > holder of metadata about the entire set of values (i.e. "ranges") of
a
>> set
>> > of higgins:attributes
>> >
>> > Changes have been published here [1]
>> >
>> > [1] http://www.eclipse.org/higgins/ontologies/2006/higgins.owl
>> >
>> > -Paul
>> >
>> > _______________________________________________
>> > higgins-dev mailing list
>> > higgins-dev@xxxxxxxxxxx
>> > https://dev.eclipse.org/mailman/listinfo/higgins-dev
>>
>> _______________________________________________
>> higgins-dev mailing list
>> higgins-dev@xxxxxxxxxxx
>> https://dev.eclipse.org/mailman/listinfo/higgins-dev
>
> _______________________________________________
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> https://dev.eclipse.org/mailman/listinfo/higgins-dev

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