Hoi, Sorry for being dense.. What is wrong with there being no value ?

"no value" is imho understanding only a complication of saying

Why not say nothing in the first place ?

So the intention is to use Q19798647 as a random place holder specifically for Wikibase entities without a value, but not as a "no value" placeholder for a person? I think it is useful in the way you describe it, but I am curious how you would model the source B saying that "X had no child" On Thu, Apr 23, 2015 at 11:37 AM, Lydia Pintscher < lydia.pintscher(a)wikimedia.de&gt; wrote: > On Thu, Apr 23, 2015 at 11:33 AM, Gerard Meijssen > &lt;gerard.meijssen(a)gmail.com&gt; wrote: > > Hoi, > > Sorry for being dense.. What is wrong with there being no value ? > Having a > > "no value" is imho understanding only a complication of saying > nothing... > > Why not say nothing in the first place ? > > It is important for cases like the following for example: Source A > says "X had a child" and source B says "X had no child". > > > Cheers > Lydia > > -- > Lydia Pintscher - http://about.me/lydia.pintscher > Product Manager for Wikidata > > Wikimedia Deutschland e.V. > Tempelhofer Ufer 23-24 > 10963 Berlin > www.wikimedia.de > > Wikimedia Deutschland - Gesellschaft zur Förderung Freien Wissens e. V. > > Eingetragen im Vereinsregister des Amtsgerichts Berlin-Charlottenburg > unter der Nummer 23855 Nz. Als gemeinnützig anerkannt durch das > Finanzamt für Körperschaften I Berlin, Steuernummer 27/681/51985. > > _______________________________________________ > Wikidata-l mailing list > Wikidata-l(a)lists.wikimedia.org > https://lists.wikimedia.org/mailman/listinfo/wikidata-l > _______________________________________________ Wikidata-l mailing list Wikidata-l(a)lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-l

Hi Thomas, On 22.04.2015 20:06, Thomas Douillard wrote: > Hi, there is items about Wikibase data model in Wikidata (created by > me, > but not only) > > If I understand correctly, they could be cited in the semantic web as > https://www.wikidata.org/entity/Q19798647 > "No value" is exactly that: not a value. It should not be confused with a (definite) value that is used with claims (as the item description seems to suggest). The reason why we introduced "no value" was to be able to say this without resorting to a "special value" to represent this. You can also find some rationale about this in our article "Wikidata: a free collaborative knowledgebase" (see https://ddll.inf.tu-dresden.de/web/Article4002/en). Basically, the main point is that, if you are querying for two people with a common child, you wouldn't want to get pairs of people who both have "novalue" as a value for "child". The same is true for "some value" (sometimes referred to as "unknown value") -- again, if this would be a definite "special" value, and be treated like a value in queries, it would lead to wrong results. Cheers, Markus > (If they are kept /o\) > > Tom² > > > _______________________________________________ > Wikidata-l mailing list > Wikidata-l(a)lists.wikimedia.org > https://lists.wikimedia.org/mailman/listinfo/wikidata-l > > _______________________________________________ Wikidata-l mailing list Wikidata-l(a)lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-l

In wikidata, the absence of a claim about something cannot mean the claim has no couterpart in reality, as Wikidata is an will always be incomplete. For example if we have a series, maybe finished, maybe unfinished, we wil have claims that says: Episode 2 follows Episode 1 Episode 3 follows Episode 2 ... If for some reason we're sure that the series is other, we can state no value follows Episode 2 Which means "We're sure the series is other". Otherwise this means "Wikidata do not know", for some reason there could be a following episode but noone updated Wikidata yet, for example. 2015-04-23 11:33 GMT+02:00 Gerard Meijssen &lt;gerard.meijssen(a)gmail.com&gt;om>: > Hoi, > Sorry for being dense.. What is wrong with there being no value ? > Having a "no value" is imho understanding only a complication of saying > nothing... Why not say nothing in the first place ? > Thanks, > GerardM > > On 22 April 2015 at 21:52, Markus Krötzsch < > markus(a)semantic-mediawiki.org&gt; wrote: > >> Hi Thomas, >> >> On 22.04.2015 20:06, Thomas Douillard wrote: >> >>> Hi, there is items about Wikibase data model in Wikidata (created by >>> me, >>> but not only) >>> >>> If I understand correctly, they could be cited in the semantic web as >>> https://www.wikidata.org/entity/Q19798647 >>> >> >> "No value" is exactly that: not a value. It should not be confused >> with a (definite) value that is used with claims (as the item description >> seems to suggest). The reason why we introduced "no value" was to be able >> to say this without resorting to a "special value" to represent this. >> >> You can also find some rationale about this in our article "Wikidata: >> a free collaborative knowledgebase" (see >> https://ddll.inf.tu-dresden.de/web/Article4002/en). Basically, the >> main point is that, if you are querying for two people with a common child, >> you wouldn't want to get pairs of people who both have "novalue" as a value >> for "child". The same is true for "some value" (sometimes referred to as >> "unknown value") -- again, if this would be a definite "special" value, and >> be treated like a value in queries, it would lead to wrong results. >> >> Cheers, >> >> Markus >> >> >>> (If they are kept /o\) >>> >>> Tom² >>> >>> >>> _______________________________________________ >>> Wikidata-l mailing list >>> Wikidata-l(a)lists.wikimedia.org >>> https://lists.wikimedia.org/mailman/listinfo/wikidata-l >>> >>> >> >> _______________________________________________ >> Wikidata-l mailing list >> Wikidata-l(a)lists.wikimedia.org >> https://lists.wikimedia.org/mailman/listinfo/wikidata-l >> > > > _______________________________________________ > Wikidata-l mailing list > Wikidata-l(a)lists.wikimedia.org > https://lists.wikimedia.org/mailman/listinfo/wikidata-l > > _______________________________________________ Wikidata-l mailing list Wikidata-l(a)lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikidata-l