Re: Proposal: 6NF

vc wrote:
> Jan Hidders wrote:
> > vc wrote:
> > But the constructions together with the operations that are defined
> > along with them, *do* satisfy the expected properties.
>
> How would Q *without* division or Z *with* division (since that's what
> you would have to do with at least one of them in order for the LSP to
> work) satisfy what one expects from Q and Z in math ?

Where do you get the strange idea that LSP requires that there should be a division within my defined Z that results in an element from Z? You keep on saying that, and I have no idea why you think that. Demonstrating that there is a problem should be simple. You could give a well-typed expression that has a certain result, and if you replace certain constants of type t1 in that expression with the corresponding constants in a subtype t2 then the result of the expression changes. Can you give me such an expression?

Since I think this is the core issue I'll limit my reply to this. I had actually written also replies to your other remarks, but we can always get to that later. It would be a pity if the discussion would grind to a halt because of discussion fatigue. :-)

• Jan Hidders