[dxwg] Domain, range and usage of dcat:first, dcat:last is hard to understand (#1513)

stigbd has just created a new issue for https://github.com/w3c/dxwg:

== Domain, range and usage of dcat:first, dcat:last is hard to understand ==
In an early attempt to use the much welcomed `dcat:DatasetSeries`, I find it hard to understand how dcat:first and dcat:last is to be used.

None of the examples show the usage of these properties.

Based on the assumption that domain/range is `dcat:DatasetSeries`/`dcat:Dataset` and what I think is the intention behind these properteis, this should work as an example:
```
ex:EUCatalogue a dcat:Catalog ;
  dcterms:title "European Data Catalogue"@en ;
  dcat:dataset ex:budget , ex:employment , ex:finance ;
  .

ex:budget a dcat:DatasetSeries ;
  dcterms:title "Budget data"@en ;
  dcat:first ex:budget-2018 ;
  dcat:last ex:budget-2020 ;
  .
  
ex:budget-2018 a dcat:Dataset ;
  dcterms:title "Budget data for year 2018"@en ;
  dcat:inSeries ex:budget ;
  .
  
ex:budget-2019 a dcat:Dataset ;
  dcterms:title "Budget data for year 2019"@en ;
  dcat:inSeries ex:budget ;
  .
  
ex:budget-2020 a dcat:Dataset ;
  dcterms:title "Budget data for year 2020"@en ;
  dcat:inSeries ex:budget ;
  .
```

I suggest you include domain, range and an example showing the usage of these properties.

Please view or discuss this issue at https://github.com/w3c/dxwg/issues/1513 using your GitHub account


-- 
Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config