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 [EMAIL PROTECTED] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] 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? ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org
