RE: [boost] Interval Library and comparison operators

From: David Bergman (davidb_at_[hidden])
Date: 2002-09-06 11:19:04

I could object to A == A being indeterminate, though, which is the case
with the "forall"-definition.

You could also look at an earlier post by Joel, where he uses, as an
example, "exists"-definitions, which do the contrary, i.e., expand
instead of contract.

I do object in contracting '==' so that ' A == A ' becomes non-true.
IMEHO, that is contracting too far (or, in other words, being too
cautious)

A naive question: what is the benefit of using tribools in this interval
domain?

/David

-----Original Message-----
From: boost-bounces_at_[hidden]
[mailto:boost-bounces_at_[hidden]] On Behalf Of Douglas Gregor
Sent: Friday, September 06, 2002 12:08 PM
To: boost_at_[hidden]
Subject: Re: [boost] Interval Library and comparison operators

On Friday 06 September 2002 11:48 am, David Bergman wrote:
> In the 3-state relation it should mean "possibly not reflexive" as in 
> "A RelOp B yields something different from 'true'"
>
> In fact, I was objecting to the 2-state definition, of
>
> 	[a1, a2] RelOp [b1, b2]   iff   forall a1 <= a <= a2, b1 <= b <=
> b2: a RelOp b
>
> Where "irreflexive" really means something...
>
> /David

Fair enough. I'm interested only in the 3-state definition. The 2-state 
definition is just narrowing indeterminate->false.

        Doug
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