Re: [boost] Interval Library and comparison operators

From: Joel Young (jdy_at_[hidden])
Date: 2002-09-06 09:13:32

--------
From: Douglas Gregor <gregod_at_[hidden]>
> On Thursday 05 September 2002 11:59 pm, Joel Young wrote:
> > From: Douglas Gregor <gregod_at_[hidden]>
> > > I can vouch for the need for the definition:
> > > [a,b] RelOp [c,d] := x RelOp y for all (x, y) where a <= x <= c, b <= y
> > > <= d
> >
> > Could you describe some of the RelOps you find interesting?
> 
> <, <=, ==, !=, >=, > are all useful for me. Basically, I just need the 
> ...
> The result may be (always) true, (always) false, or indeterminate. 

Could you give me an example of two intervals and a relop you consider
indeterminate? 

What does the ":=" symbol mean?  iff?

[a,b] RelOp [c,d] := 
   x RelOp y for all (x, y) where a <= x <= c, b <= y <= d

I think for three-valued logic, the above definition isn't sufficient.
Am I missing something?

Joel