Re: A statement on dbdebunk.

Erwin wrote:
> Keith,
>
> > He did not mean (nor did he state) isomorphism. He
> > stated the mapping is 1:1. ... He seems to say that
> > there are conceptual elements that are not mapped to the
> > logical model.
>
> So when he *states* that some mapping is 1:1, then
> according to you, he is actually saying that there are
> certain elements that do not map ?????????????

It seems that is exactly what he said:

"Logical model: formal representation (as much semantics as a system is capable of "understanding")".

In other words, some concepts are not mapped to the logical model (according to my reading of him and a dash of common sense).

> > Remember that isomorphism is 1:1 /and ONTO/. The mapping
> > is not onto.
>
> Can you please explain precisely what difference is made
> by /and ONTO/ ??? I don't understand where you're getting
> at here. What is the difference between mappings that are
> indeed "onto" and other mappings that are not "onto"
> ??????

Chris has explained some of this. You can search for more using keywords such as: bijective, injective, surjective, partial function, total function, etc. Indeed, someone throwing about the word "isomorphism" and using it for argumentation should at least be aware of those terms.

By the way, is your '?' key stuck? Try keeping the Kool-Aid away from your computer.

• Keith -- Fraud 6