Re: abstract + nillable = ?

> On 15 Dec 2016, at 16:42, Ihe Onwuka <ihe.onwuka@gmail.com> wrote:
> 
> If an element is specified as both abstract and nillable what domain if any does the nillable hold over the substituting element.
> 
> I am trying to figure out what was intended by the author of a schema that does this.


See Content type restricts (Complex Content), clause 4.1

G subsumes S if G.{nillable} = true or S.{nillable} = false

That basically means that if a supertype contains a non-nillable element, it can't be substituted in a subtype with a nillable element. So if you're creating an abstract element and you want the concrete elements to be nillable, then the abstract element has to be nillable.

Michael Kay
Saxonica