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From: Terry Lambert <tlambert@primenet.com>
Message-Id: <199709252225.PAA04200@usr04.primenet.com>
Subject: Re: new timeout routines
To: bde@zeta.org.au (Bruce Evans)
Date: Thu, 25 Sep 1997 22:25:12 +0000 (GMT)
Cc: bde@zeta.org.au, tlambert@primenet.com, current@FreeBSD.ORG,
        gibbs@plutotech.com, julian@whistle.com, nate@mt.sri.com
In-Reply-To: <199709251144.VAA13138@godzilla.zeta.org.au> from "Bruce Evans" at Sep 25, 97 09:44:49 pm
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> >> Now it is (almost) idempotent (N = 1 in the above), provided the
> 
> This is correct.  Idempotence (for an element x in a set with a binary
> operation '*') is x*x = x.
> 
> >Actually, this is "called reflexively".
> 
> Wrong.  Reflexivity (for an element x in a set with a binary relation
> R to itself) is xRx.

Heh.  You omitted the provision stated in "provided the ...".

The "called reflexively" referred to a one-to-one relationship between
enqueing and dequeueing (or expiration) of timers.  If you call untimeout
more times than you call tiemout, then it's not "called reflexively".

> >   Date: 1870
> >   : relating to or being a mathematical quantity which when applied to
> >   itself under a given binary operation (as multiplication) equals
> >   itself; also : relating to or being an operation under which a
> >   mathematical quantity is idempotent
> >   - idempotent noun
> 
> This is correct :-).  There must be a binary operation (i.e., a mapping
> SxS -> S), not just a self-relation (i.e., a mapping SxS -> {0, 1}) to
> define idempotence.

Right.  Yielding the identity set is not sufficient (ulnless what you
are testing for idempotence is the identity set.  8-)).  Give them a
break, it was 1870.  ;-).


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.