Re: what are keys and surrogates?

Marshall wrote:

>Suppose we wish to model what children someone has. (Using
>int ids for the sake of brevity.)
>
>{(parent=1, child=2), (parent=1, child=3)}
>
>Suppose we do it this way:
>
>{(parent=1, child={2, 3})}
>
>Why should either of these two ways raise any philosophical issues?

As long as you promise to consistently use this cross-translation to define the meaning of nested values whenever they are used, the difference is only a representational detail.

-- 
Reinier