From: William Arthur Naylor <bill@scl.csd.uwo.ca>

Date: Wed, 20 Jun 2001 17:06:01 -0400 (EDT)

To: Robert Miner <RobertM@dessci.com>

cc: dreamthnk@hotmail.com, www-math@w3.org

Message-ID: <Pine.LNX.4.21.0106201656160.10588-100000@millennium.scl.csd.uwo.ca>

Date: Wed, 20 Jun 2001 17:06:01 -0400 (EDT)

To: Robert Miner <RobertM@dessci.com>

cc: dreamthnk@hotmail.com, www-math@w3.org

Message-ID: <Pine.LNX.4.21.0106201656160.10588-100000@millennium.scl.csd.uwo.ca>

On Wed, 20 Jun 2001, Robert Miner wrote: > > > i was just wondering if there was a way to apply certain characters, for > > example "plusminus" or "plusmn" as content mathml as opposed to leaving it > > as presentation mathml since the symbol is not just a constant, but rather > > represents an operation. > > This is kind of a tricky case. The plusminus symbol is usually really > used as a shorthand for two separate operators. One could try to > define a plusminus operator that maps from RxR -> RxR, so that > > > 3 plusminus 5 = (8, -2) > > or something like that, but then you have problems extending all your > other operators to work on lists, e.g what does (3 plusminus 5) * 2 > mean? The * isn't ordinary multiplication anymore, since the operand > on the left is now an ordered pair. > > For content encoding, probably the better way to go is to use the > logic contructs, or possible the list construct to write down both the > result of adding and subtracting the arguments. Thus, the presentation > MathML > > <mrow><mn>3</mn><mo>±</mo><mn>5</mn></mrow> > > best corresponds to a content encoding like > > <list> > <apply><plus/><cn>3</cn><cn>5</cn></apply> > <apply><minus/><cn>3</cn><cn>5</cn></apply> > </list> This would be nice, though the ordering is artificial, it would be better if we used/had some sort of tuple construct > > <apply> > <or/> > <apply><plus/><cn>3</cn><cn>5</cn></apply> > <apply><minus/><cn>3</cn><cn>5</cn></apply> > </apply> > of course this should return a boolean, and in fact makes no sense when applied to plus and/or minus, unless their meanings where overridden using the 'definitionURL' attribute (what would that mean for 'minus'!), Bill. --Received on Wednesday, 20 June 2001 17:06:08 UTC

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