Hoi,
Absolutely..

When full genealogy information is available, you do not need special words that indicate whatever. It is only when this is not the case that you need to specify what type of link there is. This can be specific like maternal uncle or paternal aunt. This makes a practical difference in several cultures and is THEREFORE significant. Again, it is only of relevance when it cannot be inferred.
Thanks,
      GerardM

On 27 August 2015 at 11:08, Marielle Volz <marielle.volz@gmail.com> wrote:
If you want to find all humans on wikidata, find all items with the
property "instance of" (p35) equal to "human" (q5). There is no need
to infer this from things like having the parent property, that's a
terrible way to do things. Items that are instances of different items
use the same properties all the time, you shouldn't be inferring
anything about the class of an item based on the properties it has.

If you are worried about horses being put in a genealogical tree with
humans, that would require someone to put a horse as a parent of a
human or vice versa. That's an problem with an invalid relationship
being added, not the property itself.

On Wed, Aug 26, 2015 at 6:43 PM, Svavar Kjarrval <svavar@kjarrval.is> wrote:
>
>
> On mið 26.ágú 2015 13:58, Peter F. Patel-Schneider wrote:
>> I don't think that P21 (https://www.wikidata.org/wiki/Property:P21, sex or
>> gender) is a subclass of P31 (https://www.wikidata.org/wiki/Property:P31,
>> instance of).  Properties aren't subclasses in general.
>>
>> Perhaps you meant to talk about https://www.wikidata.org/wiki/Property:P21
>> (sex or gender) being related via (https://www.wikidata.org/wiki/Property:P31
>> (instance of) to https://www.wikidata.org/wiki/Q18608871 (Wikidata property
>> for items about people).   This indicates that the property should only be
>> used on people, even though the description of the property itself talks about
>> its use on animals.
>>
>> It appears that Wikidata is not very consistent internally.
>>
>> peter
>>
> Sorry, I'm not used to the Wikidata lingo.
>
> To further explain my point (to which I think you have already agreed to):
> If I were to produce a code which makes assumptions based on such
> relations, the code would come to the contradiction that a non-human
> with a P21 relation is a human, if it were to recursively travel via in
> the hierarchy of declarations. P21 is declared with a P31->Q18608871 and
> Q18608871 is in turn declared P1269->Q5. Unless special precautions
> would be taken, anyone trying to generate an exhaustive list of all
> humans on Wikidata (without relying solely on the direct declaration on
> each item), they might find themselves with non-humans on that list due
> to travelling backwards via such relations.
>
> In essence, it seems like P21 either wrongfully allows definitions of
> genders of non-humans or that the property is too broad for a
> declaration of P31->Q18608871.
>
> - Svavar Kjarrval
>
>
> _______________________________________________
> Wikidata mailing list
> Wikidata@lists.wikimedia.org
> https://lists.wikimedia.org/mailman/listinfo/wikidata
>

_______________________________________________
Wikidata mailing list
Wikidata@lists.wikimedia.org
https://lists.wikimedia.org/mailman/listinfo/wikidata