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Re: How do I encode negative numbers in content MathML?

From: David Carlisle <davidc@nag.co.uk>
Date: Tue, 16 May 2006 13:51:25 +0100
Message-Id: <200605161251.k4GCpPlH013043@edinburgh.nag.co.uk>
To: juanrgonzaleza@canonicalscience.com
CC: www-math@w3.org


> What is the difference if any between both encodings?

<cn>-2</cn> is an encoding of the negative number -2
<apply><minus/><cn>2</cn></apply> is an encoding of the unary minus
operator applied to 2.

In most mathematical contexts these are going to be equal and
interchangable. You might possibly want to distinguish between them
if you are discussing the properties of the unary minus operator.
The equation
<apply><eq/>
  <apply><minus/><cn>2</cn></apply>
  <cn>-2</cn>
</apply>
remains true, but loses the point somewhat, if you normalise both sides
of the equation to the same form.

Actually the default rendering of <cn>-2</cn> is that of <mn>-2</mn>
and it may be preferable to use <mo>-</mo><mn>2</mn> which would be
encoded as <cn><mo>-</mo><mn>2</mn></cn>.

David

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Received on Tuesday, 16 May 2006 12:53:37 GMT

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