M0061.02 Revised Flavors Text

["Corliss, George" <george.corliss@xxxxxxxxxxxxx>]

P1788,

Voting on Motion M0061.02 Revised Flavors Text extends through Friday, Feb. 28.  

Current tally: Yes - 26; No - 0; Needed for quorum - 29

Baker’s announcement of the voting period is below.

PLEASE VOTE.  Voting is lagging a little behind its usual pace.

[I am sending individualized nagging messages to those who have not yet voted, but the entire group should know where we stand.]

George Corliss,
P1788 Voting Tabulator

Begin forwarded message:

> From: Ralph Baker Kearfott <rbk5287@xxxxxxxxxxxxx>
> Subject: Motion P1788/M0061:REvisedFlavorsText -- voting period begins
> Date: February 7, 2014 at 8:24:51 AM CST
> To: John Pryce <j.d.pryce@xxxxxxxxxx>, stds-1788 <stds-1788@xxxxxxxxxxxxxxxxx>
> Reply-To: <rbk@xxxxxxxxxxxxx>
> 
> P-1788:
> 
> Voting on this motion herewith begins.  The rules for
> standard text motions apply.
> 
> Voting will continue until after Friday, February 28, 2014.
> 
> Juergen: Please update the on-line list of motions with
>   this information and the updated document.
> 
> Best regards,
> 
> Baker
> 
> On 02/03/2014 09:01 AM, John Pryce wrote:
>> P1788
>> 
>> Here is a new draft of Clause 7 "Flavors". I think the ideas
> are now made firm. There may be minor changes because of poor
> wording - please read with care, and complain about any
> obscurities. But I believe this text is ready to proceed to the
> vote.
>> 
>> The main changes are:
>> 
>> 1. A thorough revision of §7.5.3 "Level 2 operations". Following Vladik's
>> support for my thesis that "uncertainty is essential", the possibility
>> that an implementation may be unable to decide certain facts, because of
>> algorithmic constraints, is made an inherent feature of Level 2 in any
>> flavor.
>> 
>> For example the description (7.5.3 item 3(b)) of how the T-version phi_T of
>> an operation phi with decorated-interval result is handled now says
>> 
>>> If [the Level 1 result is found to exist and] is a decorated interval y_dy there are
>>> three cases.
>>> - If phi is an arithmetic operation, and [the input box] is a decorated
>>> common input (this implies dy=com, see §7.4.2), and a common T-interval
>>> z containing y is found, then phi_T returns such a z with the decoration
>>> com.
>>> - Otherwise, if a T-interval z containing y is found (in particular if
>>> Entire exists in the flavor and is a T-interval), then phi_T returns
>>> such a z with a flavor-defined decoration.
>>> - Otherwise, no such z is found. Then phi_T signals the IntvlOverflow
>>> exception and the returned result, if any, is flavor-defined.
>> 
>> Here "is found" is defined to mean that the implementation is able to compute
>> a value, or determine whether a fact is true.
>> 
>> In the first of the 3 cases above, I've kept the requirement that the returned
>> decoration is "com" -- not a possibly weaker decoration, as suggested by Michel.
>> This is because it seems to me all the bases have been covered:
>> - The input *is* a decorated common input box, meaning its components are common
>> intervals decorated "com". I said "is", not "is found to be", because I can't
>> conceive a flavor, type or implementation, where it is difficult at run time to
>> decide if a given interval is common or not. Is that reasonable?
>> - The common z containing y "is found" by the implementation. So at this point all
>> uncertainty has disappeared, and there is no reason to return a weaker decoration.
>> 
>> The terms "decorated common evaluation" and "decorated common input" have been made
>> Level 1 (not Level 2) notions, put in 7.4.2. The subsubsection after 7.4.3 that used
>> to define them has been removed.
>> 
>> 2. I have changed the exceptions "IntvConstructorFails" and "IntvConstructorUnsure" to
>> "UndefinedOperation" and "PossiblyUndefinedOperation" throughout the text, for the
>> reasons I stated before.
>> 
> 
> 
> -- 
> 
> ---------------------------------------------------------------
> R. Baker Kearfott,    rbk@xxxxxxxxxxxxx   (337) 482-5346 (fax)
> (337) 482-5270 (work)                     (337) 993-1827 (home)
> URL: http://interval.louisiana.edu/kearfott.html
> Department of Mathematics, University of Louisiana at Lafayette
> (Room 217 Maxim D. Doucet Hall, 1403 Johnston Street)
> Box 4-1010, Lafayette, LA 70504-1010, USA
> ---------------------------------------------------------------

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