Re: Clean Object Class Design -- Circle/Ellipse

>>>> >Somebody in the other thread noted that subsets in math are defined by
>>>> >predicates over containing set. I have trouble identifying a predicate
>>>> >that selects integers from the set of real numbers. Am I missing
>>>> >something obvious? This is maybe the first indicator that we don't
>>>> >want to inherit integers from reals.
>>>>
>>>> I = { r in R | floor(r) = r }
>>>
>>>I meant that universal and existential qualifiers plus ariphmetic
>>>operations are allowed only.
>>
>>What makes floor or truncate different from any other arithmetic
 operation?
>
>Definition: The real number system is that unique algebraic structure
>represented by all Dedekind-complete ordered field. (Actually, driving
>everything down to simplicity, we agreed to remove "Dedekind-complete" part
 and
>just talk about rational numbers;-) However, there is no floor() operation
 in
>the definition of either real or rational numbers.

Whose definition? Received on Sat Aug 18 2001 - 18:50:11 CEST