# Re: Counting propositions

From: x <x-false_at_yahoo.com>

Date: Tue, 22 Jun 2004 22:18:23 +0300

Message-ID: <40d884f8$1_at_post.usenet.com>

> > But not all bag operators can be decomposed in this way.

> Let's go through the list:

> AVG - nonfundamental, can be expressed in terms of SUM

>

> Do you need mere examples to be convinced that there are only 4

fundamental

Date: Tue, 22 Jun 2004 22:18:23 +0300

Message-ID: <40d884f8$1_at_post.usenet.com>

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"Mikito Harakiri" <mikharakiri_at_iahu.com> wrote in message
news:DZZBc.20$da4.283_at_news.oracle.com...

*> "x" <x-false_at_yahoo.com> wrote in message news:40d8642c_at_post.usenet.com...
*

> > **** Post for FREE via your newsreader at post.usenet.com ****

*> > > > > Count is unusual aggregate operator. Every other aggregate
*

operator

*> is
*

> > > > > associated with a binary operation. Indeed, the SUM is iterative

*> > > > application
**> > > > > of "+", the MAX is iterative application of "max(x,y)" (or CASE
**> ...).
**> > > > There
**> > > > > are few exceptions like AVG, but they can be viewed as redundant
*

(or

*> > at
*

> > > > > least less fundamental) operators.

>

> > But not all bag operators can be decomposed in this way.

>

> Let's go through the list:

>

> AVG - nonfundamental, can be expressed in terms of SUM

*> STDDEV = SQRT(VARIANCE)**> VARIANCE = (SUM(x*x)-(SUM(x)*SUM(x))/SUM(1))/(SUM(1)-1)*>

> Do you need mere examples to be convinced that there are only 4

fundamental

*> aggregate operators?***> 1. SUM = "+"***

*> 2. MIN = "/\"**

*> 3. MAX = "\/"****Nonsense.**

*> 4. LIST = "||"****SUM([1])=1.****COUNT([1,2,3,4])=4 !=SUM([1,2,3,4]).**-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Usenet.com - The #1 Usenet Newsgroup Service on The Planet! *** http://www.usenet.com Unlimited Download - 19 Seperate Servers - 90,000 groups - Uncensored -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=