[EMAIL PROTECTED] writes: > Whoops: forgot the list. > > ---------------------------- Original Message ---------------------------- > Subject: Re: [Om3] OpenMath Symbols for Symbolic Computation > From: [EMAIL PROTECTED] > Date: Wed, September 17, 2008 11:45 pm > To: "Peter Horn" <[EMAIL PROTECTED]> > Cc: "Professor James Davenport" <[EMAIL PROTECTED]> > -------------------------------------------------------------------------- > > > On Wed, September 17, 2008 12:29 pm, Peter Horn wrote: >> Hi! >> >>> I would disgaree here. A Matrix is precisely that, and needs no >>> additional >>> information. IF you wnat that matrix to represent a linear >>> transformation >>> on a space, THEN you need additional information. >> >> Well, if you want to do computations with a matrix (and that's our >> intention), you need all the information we define in matrix1. > I think I deny that. If (as I believe I can) I can multiply > <OMI>2</OMI> by <OMI>3</OMI>, then surely I can multiply > <OMA> > <OMS name="matrix" cd="linalg2"/> > <OMA> <OMS name="matrixrow" cd="linalg2"/> <OMI>2</OMI> </OMA> > </OMA> > by > <OMA> > <OMS name="matrix" cd="linalg2"/> > <OMA> <OMS name="matrixrow" cd="linalg2"/> <OMI>3</OMI> </OMA> > </OMA>. > And if I can do that, then why not 2x2 matrices, or other sizes? >>>> Sure. We want to work with matrices (and other objects) in computer >>>> algebra systems, and as you can imagine it's hard to guess (from >>>> the CAS' >>>> POV) what the user is trying to tell us when even the most basic >>>> information is missing. >>> Right - rather like the polyd family. of CDs. Having such a set of CDs >>> certainly makes sense >> >> We simply adopted the polyd ideas to matrices. >> >>> I'd be happy to look at what you have: I have Peter Horn's matrix1, >>> but don't quite see, for instance, what the point of entry_domain is? >> >> That's the ground ring. > But I don't see what it does. What does > <OMA> > <OMS name="entry_domain" cd="matrix1"/> > <OMS name="Z" cd="setname1"/> > </OMA> > have that just > <OMS name="Z" cd="setname1"/> (or ringname1 if you want) not have? [snip]
Ah, now I get you. Sure, you're right, there's no additional mathemtical information, but I (in particular) fought for that `feature' because it allows for easy xpath access whilst being flexible about the order of `arguments' within the matrix constructor. /[EMAIL PROTECTED]'matrix1' and @name='matrix_domain']]/[EMAIL PROTECTED]'matrix1' \ and @name='entry_domain']]/ is the full path to the entry domain from a matrix1.matrix parent, which is (in my opinion) clearly better than something like /[EMAIL PROTECTED]'matrix1' and @name='matrix_domain]][2]/ It's basically a major flaw IMHO in the rest of the OM CDs too. Modern XML parsers for instance allow you to lodge callback functions in certain nodes, which obviously wouldn't work if a particular node is just the second sibling of another node. I'm not particularly tied to that approach (another symbol application), it's just the only one possible at the moment. I imagine something a la: <OMS name="Z" cd="ringname1" role="entry_domain"/> or, to preserve the context that it's meant to be a ground ring of a matrix: <OMS name="Z" cd="ringname1" role="entry_domain" ctx="matrix1.matrix"/> Well, not meant as a proposal, just a note. Cheers Sebastian _______________________________________________ Om3 mailing list [email protected] http://openmath.org/mailman/listinfo/om3
