Re: representing null in semantic frameworks

Frank Manola wrote:
>
> I understand, but notice that NaN isn't really an example of the kind 
> of general null you're talking about (one that can be used with 
> arbitrary properties, as in the case of relational nulls).  Rather, 
> it's a *type-specific* (to floating point numbers) value that has a 
> type-specific meaning, and where stuff like comparisons, what happens 
> if they're used in further operations and statistical functions, etc. 
> has been worked out.

Good point.


> I'd like to see semantic frameworks be more strongly typed too (that 
> is, in the sense that there's some way of specifying all the 
> information I have about the situation to be modeled;  not necessarily 
> that I want things as rigid as is sometimes implied by "strongly 
> typed").  But I don't necessarily see that a general null that, in 
> order to be used with arbitrary properties (taking values of arbitrary 
> types) might need to mean different things for different types, 
> contributes to "strong typing".  It seems to me more likely to muddle 
> things up.

All good points. I'm going to do some researching and thinking. 
Thanks---this helps immensely.

Garret