Re: Testing for the equivalence relation

From: Dan Guntermann <guntermann_at_verizon.net>
Date: Sat, 02 Jul 2005 06:42:44 GMT
Message-ID: <EHqxe.1817$H64.756_at_trnddc07>


"Jan Hidders" <jan.hidders_at_REMOVETHIS.pandora.be> wrote in message news:I8kxe.135100$Vs4.7201818_at_phobos.telenet-ops.be...
> Dan wrote:
>> "No, there are two equivalence classes. Period. Saying that there are 4
>> is sloppy terminology."
>>
>> Equivalance classes, denoted with brackets:
>> [a] = {a, b}
>> [b] = {a, b}
>> [c] = {c, d}
>> [d] = {c, d}
>>
>> Distinct equivalence classes
>> {a,b}
>> {c,d}
>
> I have 4 sisters. There is the daughter of my father, the daughter of my
> mother, the grand-daughter of my grand-mother and the grand-daughter of my
> grand-father. Since all these girls happen to be identical I have only one
> distinct sister.
>
> Wouldn't you agree that the first sentence is a bit misleading? What I
> have 4 of is not sisters, but descriptions of my sister. What you have 4
> of is not equivalence classes, but definitions of equivalence classes.
>
Perhaps something like, "every element's equivalence class reduces to two distinct equivalence classes" would have been clearer for that particular example.

Anyway, I think I've found my answers. Thanks!

Regards,

  • Dan
Received on Sat Jul 02 2005 - 08:42:44 CEST

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