Re: Equivalence relations and "is a sibling of"

In article <1152552263.840249.272790@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
<sttscitrans@xxxxxxxxx> wrote:

[.snip.]

I ->agree<- with you that the relation "having the same parents as" is
reflexive. That is the point you make above. I am saying that your
error lies in thinking that the relation "is a sibling of" and the
relation "have the same parents as" is identical; it is not. "Sibling"
carries a lot more linguistic baggage than "the same parents".

Yes, I basically agree with you now as I have realized
that I was deluding myself into thinking that "is a sibling of"
is transitive when, of course it's not.

I never touched on the question of transitivity. Your problem lay
with reflexivity, and you were wrong to claim that "is a sibling of"
ought to be considered reflexive, and you were incorrect in equating
"is a sibling of" with "has the same parents as" or with "is as tall
as".

That was my point and my explanations.


disease sufferers analogous to "siblings"

F(x,y) means
x<>y and x suffers disease D and y suffers disease D
which implies
y<> x and y suffers diesease D and x suffers disease D
which implies F(y,x) and so F is symmetrical.
F(x,x) => x<>x and x suffers disease D and X suffers disease D
which is false and so F is never reflexive.
Does F(x,y) and F(y,x) => F(x,x) and that F is transitive ? No, because
it is not
true that x<>x.
On the other hand, if x,y,z are distinct
F(x,y) and F(y,z) =>F(x,z).

Is this basically what you mean ?

It cannot possibly be anything about what I meant, since I never
touched on transitivity. I have no idea why you would think that this
has anything whatosever to do with anything whatsoever I said in this
thread.

Unless, of course, you did not read what I wrote in this thread.

I shall bow out, since it is apparent you are
not listening, and not interested in listening.



--
======================================================================
"It's not denial. I'm just very selective about
what I accept as reality."
--- Calvin ("Calvin and Hobbes")
======================================================================

Arturo Magidin
magidin@xxxxxxxxxxxxxxxxx

.

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