[sv-ac] Re: My notes regarding 2578

Section *16.15.8 Nonvacuous evaluations* addresses vacuity for properties,
and lists each of the property operators.
Question: is there a need that vacuity of (not(p1) or p2) to match that of (p1
implies p2)?
[Ben] No because (not(p1) or p2) uses the "or" operator, and that vacuity
relationship is specified in
*e) An evaluation attempt of a property of the form property_expr1
orproperty_expr2 is nonvacuous
*
*if, and only if, either the underlying evaluation attempt of property_expr1
is nonvacuous or the*
*underlying evaluation attempt of property_expr2 is nonvacuous*
My point being that the "or" operator is different than then "implies"
operator.

[Dmitry] should we modify the vacuity definition of iff?
[Ben] The iff looks OK to me.

Ben

On Tue, Aug 2, 2011 at 11:47 AM, Little Scott-B11206
<B11206@freescale.com>wrote:

> Hi Dmitry, Ed:****
>
> ** **
>
> My thought is that iff is probably okay. ****
>
> ** **
>
> I think that in an ideal world the vacuity of not(p1) or p2 would match
> that of p1 implies p2. Based on the previous discussions I don’t believe we
> know of a consistent set of definitions where that relationship holds. I
> favor fixing the implies vacuity definition which I believe is badly
> broken. There are other warts in the definitions that will remain for the
> time being. When someone comes up with a consistent set of definitions that
> work consistently for all cases this section can then be overhauled.****
>
> ** **
>
> Thanks,****
>
> Scott****
>
> ** **
>
> *From:* owner-sv-ac@eda.org [mailto:owner-sv-ac@eda.org] *On Behalf Of *Eduard
> Cerny
> *Sent:* Tuesday, August 02, 2011 12:40 PM
> *To:* Korchemny, Dmitry; 'ben@systemverilog.us'
>
> *Cc:* sv-ac@eda-stds.org
> *Subject:* [sv-ac] RE: My notes regarding 2578****
>
> ** **
>
> There is one more question: is there a need that vacuity of ****
>
> not(p1) or p2 ****
>
> matches that of ****
>
> p1 implies p2****
>
> ?****
>
> thanks****
>
> ed****
>
> ** **
>
> *From:* owner-sv-ac@eda.org [mailto:owner-sv-ac@eda.org] *On Behalf Of *Korchemny,
> Dmitry
> *Sent:* Tuesday, August 02, 2011 1:37 PM
> *To:* 'ben@systemverilog.us'
> *Cc:* sv-ac@eda-stds.org
> *Subject:* [sv-ac] My notes regarding 2578****
>
> ** **
>
> Hi Ben,****
>
> ** **
>
> I had the following question: should we modify the vacuity definition of
> iff? Probably we can leave it as is.****
>
> ** **
>
> Thanks,****
>
> Dmitry****
>
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