Re: The naive test for equality

Marshall Spight wrote:
> Sure. Specifically, it's an equivalence relation. Let's distinguish
> between the equality relation specifically and equivalence relations
> in general. Equality is a much simpler thing.

Is it, though? We think about 1/2 = 2/4 fine even though they have different representations. Maybe you mean "identity", often shown using a variant of the equals sign with three lines instead of two?

It's rare that we use the "equals" symbol to compare two things with identical representation: 1=1, we'd use the "identity" symbol instead.

It's all about levels of abstraction: equality at the physical layer (representation) may differ from equality at the logical layer (value).

So for the underlying relational engine to compare two values for equality, it can't in general stay in the physical layer; it has just jump up into the logical layer, do the comparison, and then jump back down to the physical layer again.

Paul. Received on Tue Aug 02 2005 - 11:03:14 CDT