Re: [boost] Interval Library and comparison operators

From: Douglas Gregor (gregod_at_[hidden])
Date: 2002-09-06 09:30:37

On Friday 06 September 2002 10:13 am, Joel Young wrote:
> Could you give me an example of two intervals and a relop you consider
> indeterminate?

Sure. [3, 5] <= [4, 6] is indeterminate, because 3 <= 5 but !(5 <= 4).

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

Yes, 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?

I should rephrase that:

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

(Conjunction is the 3-valued logic conjunction).

Is that clearer?

        Doug