RE: [boost] powerset

From: David Bergman (davidb_at_[hidden])
Date: 2002-08-29 12:37:54

Victor,

I really hope everyone here knows what a (mathematical) powerset is...
But, one could always argue for the "hip" interpretation of "powerset"
as in "mighty POWERful SET abstraction" ;-)

The good ol' cardinality jumper, P(s)...

/David

-----Original Message-----
From: boost-bounces_at_[hidden]
[mailto:boost-bounces_at_[hidden]] On Behalf Of Victor A. Wagner,
Jr.
Sent: Thursday, August 29, 2002 3:33 AM
To: boost_at_[hidden]
Subject: Re: [boost] powerset

At Wednesday 2002/08/28 12:41, you wrote:
>On Wed, 28 Aug 2002, Dave Gomboc wrote:
>
> > > >If all the elements of the set are known at compile time, why do 
> > > >you need to store the bits at all? Your class can encode the 
> > > >information in its type, thus, your class can consume zero bytes.
> > >
> > > right up until you need to add (or subtract) something that isn't 
> > > knows until runtime.
> >
> > ...which doesn't always happen.  There are certainly things I could 
> > use it for at compile-time, rather than my existing practice of 
> > generating a header file containing an array of magic numbers with 
> > an external program.
> >
> > Back to naming: this new proposed set is no more discrete than the 
> > STL's set, so "discrete_set" is a misnomer.  I think that the best 
> > name I've heard so far here for it (other than "set", which is taken

> > :-) is "powerset".  Was there something wrong with that suggestion?
> >
>
>Hello,
>
>Nothing personal but this reference to powerset causes me to cringe as 
>inconsistent with the accepted definition of "power set."

you'll provide us a definition that is "accepted" right??  Apparently
the 
one following isn't.

I'm quoting here from "CRC Concise Encyclopedia of Mathematics" Power
Set Given a SET S, the POWER SET of S is the SET of all SUBSETS of S.
The 
order of a POWER set of a SET of an order n is 2^n.  Power sets are
larger 
than the sets associated with them.

>There's a large body of mathematical terminology (and mathematics 
>itself) borrowed and integrated into CS.  Can we please try to be 
>consistent and non-contradictory in language in order to avoid 
>unnecessary confusion?
>
>I don't read this list as carefully as I would like, so apologies for 
>butting in here.  In the future I'll try to follow these threads more 
>carefully.
>
>
>Sincerely,
>Kathy Gerber
>
>
>
>
>
> > Also (albeit without having put much thought into it) it seems to me

> > that there ought to be a lot of overlap with bitset/dyn_bitset/etc.

> > Can all of these be rolled into one somehow?
> >
> > Dave
> >
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Victor A. Wagner Jr.      http://rudbek.com
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