On Mon, May 29, 2006 at 03:10:09PM -0500, Jonathan Ray wrote:

On 5/28/06, Ben Artin <macdev@artins.org> wrote:

...

Wait a minute... please name one physical quantity that is

a) Always integer b) Never negative c) Not just an enum (i.e., not just a finite set of possible values)

I can't think of one, which makes me think that your argument about physical values is irrelevant, as you'd never use an unsigned *integer* for a physical value.

Here's three: 1. Counting *anything*

This is more a case where you restrict yourself to addition, and therefore never *need* negative numbers. But why would you want a type for which operator- is not defined? You can count using a normal integer just as well and then you can ALSO answer questions like: If I have 8 cows and I give 3 cows to my neighbor, then how many will I have left? (You need to use -3 in that case; note that 8 - 3 *is* the same as 8 + (-3) in every way. As soon as substraction is defined, you should have negation, too).

2. Quantum states

Quantum states are solutions to equations. Those solutions are discrete and therefore countable. They are physical, and therefore finite. But they are no more than an enumeration of possible solutions. I can't see how you want to define addition of different quantum states-- and even if you find a way, then I'm pretty certain that zero doesn't exist.

3. Harmonic resonance

This is a special case of Quantum states. Also solutions to equations. -- Carlo Wood <carlo@alinoe.com>