Re: Real world issue:- OT recreational interval

Marshall ha scritto:

> > A binary function f(x,y) is called idempotent if for all x
> >
> > f(x,x) = x
>
> Yes, this is exactly what I've been saying, and what's been
>
> You still don't understand how binary functions are used
> In it, I said "If the binary form of the aggregate
> function is idempotent, the aggregate will return the same value
> even if values are repeated arbitrarily. Since + is not idempotent,
> sum() is "sensitive" to repeated values. Since binary min *is*
> idempotent, aggregate min() is not "sensitive" to repeated
> values."
>

Marshall,

Your statement

"If the binary form of the aggregate
function is idempotent, the aggregate will return the same value even if values are repeated arbitrarily. Since + is not idempotent, sum() is "sensitive" to repeated values. Since binary min *is* idempotent, aggregate min() is not "sensitive" to repeated values."

is TRUE. I already told you 40 posts ago. .

   what it states is formally:

   idempotent => "Not replication sensitive"

This is true. What I am stating is that

  "Not replication sensitive" => "binary idempotent"

is a false statement.

In fact:

1. Count Distinct is "Not Replication sensitive" but also 2 Count Distinct is not binary Idempotent e.g. countDistinct (5,5) = 1 => Count distinct is not binary idempotent

so it is NOT true that

 "Not replication sensitive" => "idempotent"

Therefore

  binary idempotent <=> "Not replication sensitive"

does not hold.

If it does not hold for the binary case (n=2), it does not hold in general.

This is elementary logic. I have started from the definition.

This is not philosophy. Please use logic/math argument to respond. Do not just say that I do not understand. That's not a logic argument.

If my argument has a flaw, please, Marshall or Bob or anyone, point out * exacly where it is * so that I can see it.

I am not afraid to recognize it.

-P

> Marshall
Received on Mon Sep 18 2006 - 09:27:25 CEST