Re: Clean Object Class Design -- Circle/Ellipse
Date: Sat, 18 Aug 2001 03:58:20 GMT
Message-ID: <wJlf7.5774$2u.54097_at_www.newsranger.com>
In article <WSkf7.38$Z5.11128979_at_radon.golden.net>, Bob Badour says...
>
>
>Mikito Harakiri wrote in message ...
>>"Bob Badour" <bbadour_at_golden.net> wrote in message
news:<I6Ya7.220$Vv5.18784357_at_radon.golden.net>...
>>> >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. Received on Sat Aug 18 2001 - 05:58:20 CEST