[FRIAM] Can you guess the source.

[Frank Wimberly]

Short math lesson:  A relation on a set A is a set of ordered pairs of
elements of A.  That is it is a subset of A x A.  It is reflexive iff
xRx (i.e. (x, x) is in R) for all x in A.  If xRx is false for any x in
A, the relation is not reflexive.  There are many non reflexive
relations.  For instance, "brother of" is non-reflexive in the set of
Friam "members". No one is his own brother.

I am not aware of any definition of "discrimination power" in this
context.

Additional properties of relations:

If xRy and yRz implies xRz for all x, y, z in A then R is called
transitive (in A).

If xRy implies yRx for all x,y in A then R is called symmetric (in A).

Frank 

---
Frank C. Wimberly
140 Calle Ojo Feliz              (505) 995-8715 or (505) 670-9918 (cell)
Santa Fe, NM 87505           wimberly3 at earthlink.net

-----Original Message-----
From: friam-bounces at redfish.com [mailto:friam-bounces at redfish.com] On
Behalf Of Marcus G. Daniels
Sent: Sunday, April 15, 2007 9:32 AM
To: The Friday Morning Applied Complexity Coffee Group
Subject: Re: [FRIAM] Can you guess the source.

Michael Agar wrote:
> "Reflexivity" is one of those terms...  Nice and neat in set theory,  
> a relation R is reflexive in set A  iff for all a in A aRa is true.  
>   
Question is, what is the discrimination power of R?  Does it ever say 
false?   (Unlike, say, Freud's theories or religious dogma), and if so 
does it report `true' and `false' in any pattern that rarely would occur

by chance?  Are their precise metrics for the features that R draws 
upon, or does the meta-analyst just have that convenience?

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