Re: A statement on dbdebunk.

Erwin wrote:
> "My material is sound because unlike all the stuff
> floating in the industry, the logical level is formal and
> the conceptual level was developed to allow 1:1 mapping to
> it.
>
> Conceptual model: informal business concepts
> (enterprise-specific)
>
> Logical model: formal representation (as much semantics as
> a system is capable of "understanding")
> (enterprise-specific)"
>
> Conceptual model === INFORMAL
> Logical model === FORMAL
> Conceptual model "ALLOWS A 1:1 MAPPING" to the logical
> model

Note also that "as much semantics as a sytems is capable of 'understanding'". That confirms that

> Now, it seems to me that "allows a 1:1 mapping" means that
> there is some kind of isomorphism between the things that
> are mapped in such way.

He did not mean (nor did he state) isomorphism. He stated the mapping is 1:1. Remember that isomorphism is 1:1 /and ONTO/. The mapping is not onto. He seems to say that there are conceptual elements that are not mapped to the logical model.

> And the fact that some kind of isomorphism between two
> things can be found, implies that any quality or property
> that holds/exists/is proven for either of the things
> mapped, necessarily also holds/exists for the other thing
> mapped.
>
> So if model X has the property of being formal in some
> sense, and model Y is in some way isomorphic to model X,
> then it necessarily follows that model Y is also formal in
> that same sense as model X is formal .
>
> So the statements quoted here, seem contradictory to me,
> if not quackery.
>
> Anyone care to correct me on this, or comment in any other
> way?

You assumed isomorphism and reached a contradiction. Your premise was simply false. At least it appears so given the excerpt.

Does this clear it up or am I missing something too?

• Keith -- Fraud 6