From: Bill Naylor <Bill.Naylor@mcs.vuw.ac.nz>

Date: Wed, 23 Jul 2003 13:13:44 +1200 (NZST)

To: "Roger L. Costello" <costello@mitre.org>

cc: www-math@w3.org

Message-ID: <Pine.SOL.4.51.0307231235330.17275@debretts.mcs.vuw.ac.nz>

Date: Wed, 23 Jul 2003 13:13:44 +1200 (NZST)

To: "Roger L. Costello" <costello@mitre.org>

cc: www-math@w3.org

Message-ID: <Pine.SOL.4.51.0307231235330.17275@debretts.mcs.vuw.ac.nz>

Hi Roger, Your e-mail raises an interesting point as regards to the tolerance parameter to specify an "amount of slack" value for set membership. There is an <approx/> element in the MathML spec. which one might hope could be used for this purpose. However, that doesn't seem to give any control over the accuracy of the approximation! There is an equivalent OpenMath symbol in the cd relation1, but as it is only intended for OpenMath/MathML alignment, that too doesn't give any accuracy. I have for a while argued for an approx with accuracy and I guess that a relation2 cd could be written which included such a symbol, then this cd may be submitted to the OpenMath submission site: http://monet.nag.co.uk/cocoon/openmath/cdfiles/contrib/index.html This will put it in the submitted cd's. I think then that the intention is that periodically the OpenMath organisation will review these cd's and include the ones it agrees with as official (David (Carlisle) can you correct me if I'm wrong). Given the cd's have been set up as above (an approx symbol in relation2, where the first arg is the accuracy, 2nd and 3rd approx eq), the example may be given as: <Class id="Distance"> <equivalentInstances> <!-- S = {k, m | k = m * 1.62} --> <math> <declare type="set"> <ci>S<ci> <set> <bvar definitionURL="http://www.openmath.org/cd/units_metric#kilometer"><ci>k</ci> </bvar> <bvar definitionURL="http://www.openmath.org/cd/units_imperial#mile"><ci>m</ci> </bvar> <condition> <apply> <approx definitionURL="http://www.openmath.org/cd/relation2#approx"/> <cn>-2</cn> <!-- the val is the exp of 10 --> <ci>k</ci> <apply> <times/> <ci>m</ci> <cn>1.62</cn> </apply> </apply> </condition> <list><ci>k</ci><ci>m</ci></list> </set> </declare> </math> </equivalentInstances> </Class> I think that will do what you want? If things have not been set up as required in an OpenMath CD, it is sometimes possible to use the MathML semantics element to specify the required semantics. The syntax of this element is described in the MathML spec: http://www.w3.org/TR/MathML2/chapter4.html#N36079 I hope this helps, BillReceived on Tuesday, 22 July 2003 21:14:12 GMT

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