Re: Using the RM for ADTs

On Jul 3, 5:23 am, "Brian Selzer" <br..._at_selzer-software.com> wrote:

> I think it might be simpler to assign artificial identifiers to the
> components instead of the nodes. It is certainly more intuitive. Each
> component has a finite number of leads, and each lead can connect with zero
> or more components, possibly other leads on the same component. For
> example, a NOR gate becomes an inverter if you tie the inputs together. The
> circuits can then be represented entirely as a set of unordered pairs:
>
> {{component, lead}, {component, lead}}

Consider a node to which n components are connected and n is large. Using pairwise connections can either be exceedingly arbitrary (by only representing n-1 pairs) or it makes for enormous redundancy (by representing all n(n-1)/2 pairs).

I think this is much worse that the symmetry problem with resistors.

Note that netlists used by circuit simulation programs like SPICE tend to use something similar to what I discussed - i.e. for each component list all the nodes to which it is connected. One difference is that they require component labels as well as node labels.

> I think that for components with two leads that can operate in either
> orientation, if the lead identifiers were also treated like bound variables,
> along with the component identifiers, then circuits would still be
> considered equivalent even if one or more of the components that can be
> reversed are.

You might to be onto something there. I've also been thinking that the concept of bound variables could be relevant. I came at this by thinking about the idea of instantiating circuit values within containing circuits. To achieve circuit reuse I was thinking that circuit values must be named (so they can be referenced by name in order to be instantiated within another circuit).

> The definition of an entity relation according to its properties or to
> a specific context is not a relational definition.

You're repeating Cimode? Received on Fri Jul 03 2009 - 03:27:54 CEST