Re: Historical events

That's right Thad, Wikidata and LCSH also serve as controlled vocabularies,
but having instances is what makes it valid for them have the term I think.

There are two main ways to define a type:

   - Intensional definition - give necessary and sufficient conditions for
   any thing to be an instance.
   - Extensional definition - list all the instances.

A summary is here:

https://en.wikipedia.org/wiki/Extensional_and_intensional_definitions


Because Wikidata and LCSH have instance data they can simply say "These
specific events are time periods", so they can do an extensional
definition. Schema on the other hand has no instance data, so it can only
do an intensional definition, and I argue there isn't one.

You'll end up with the same problems that CreativeWork, Product, and
Intangible create because they don't have clear meaning - an infinite
number of "Is it or isn't it?" questions.

For example, if you have:

*Event*
*    TimePeriod*


Are all papal reigns time periods? If so:

*Event*
*    TimePeriod*

        *PapalReign*


Or are only some? If so:

*Event*

    *PapalReign*
*    TimePeriod*


Is there a clear definition that makes time periods, or eras etc.,
different from events?

Anthony

On Tue, Jun 19, 2018 at 11:50 AM Anthony Moretti <anthony.moretti@gmail.com>
wrote:

> Isn't it already modeled by these properties?:
>
>    - https://webschemas.org/subEvent
>    - https://webschemas.org/superEvent
>
> Events can exist in part-whole hierarchies, aren't named periods just
> events high in these hierarchies?
>
> Anthony
>
> On Tue, Jun 19, 2018 at 11:43 AM Muri, Allison <allison.muri@usask.ca>
> wrote:
>
>> On Jun 19, 2018, at 12:34 PM, Richard Wallis <
>> richard.wallis@dataliberate.com> wrote:
>>
>> In simple terms I think Event could benefit from a property with a name
>> that means ‘when’ - the period in which the even took place.  Unfortunately
>> I believe a property named ‘when’ would be widely misunderstood
>> and misused, so I suggest the fairly ugly*periodEventOccured* which could
>> take ether a Text or URL (perhaps of a Wikidata description of
>> the period).  Maybe there is potential also for an Event Subtype of
>> *Period* that could also be used here, but maybe that is one step too
>> far until we see how things are used in the wild.
>>
>>
>>
>> Hi Richard,
>>
>> I was playing around with a property called period
>> https://sdo-historical.appspot.com/period
>>
>> description: A length of time in history characterized by some prevalent
>> or distinguishing condition, circumstance, phenomenon, influence, etc., or
>> by the rule of a particular government, dynasty, etc.; an age, era.
>>
>> microdata:
>>
>>
>>    1. <!-- Uses both the "Event" and "HistoricalEntity" item types -->
>>    2. <p itemscope="" itemtype="http://schema.org/Event">
>>    3.   <link itemprop="additionalType" href="http://schema.org/HistoricalEntity" />
>>    4.   The
>>    5.     <span itemprop="name">demolition of the Berlin Wall</span>
>>    6.   at the end of <span itemprop="period">the Cold War</span>
>>    7.     <span itemprop="geo" itemscope itemtype="http://schema.org/GeoCoordinates">
>>    8.       <meta itemprop="latitude" content="52.5161111" />
>>    9.       <meta itemprop="longitude" content="13.3769389" />
>>    10.     </span>
>>    11.   began the evening of
>>    12.     <span itemprop="startDate" content="1989-11-09">9 November 1989</span>
>>    13.     <link itemprop="sameAs" href="https://www.wikidata.org/wiki/Q11910498"/>
>>    14.   and continued over the following days and weeks, with people nicknamed Mauerspechte (wall woodpeckers) using various tools to chip off souvenirs, demolishing lengthy parts in the process, and creating several unofficial border crossings.
>>    15. </p>
>>    16.
>>
>>
>>
>> ....................................................
>> Allison Muri
>> Department of English
>>
>> Arts 418
>> University of Saskatchewan
>> Saskatoon, SK, Canada
>> ph: 306.966.5503
>>
>>