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Re: matrixcol element

From: Russell Steven Shawn O'Connor <roconnor@wronski.math.uwaterloo.ca>
Date: Fri, 13 Mar 1998 23:17:54 -0500 (EST)
To: www-math@w3.org
Message-ID: <Pine.SOL.3.95q.980313231706.23532C-100000@wronski.math.uwaterloo.ca>
On Fri, 13 Mar 1998, Richard J. Fateman wrote:

> you mean matrixcol(m,c) = matrixrow(transpose(m),c) or some such.
> If we had an appropriate object-oriented approach, then optional
> methods could trade off between storage /access / time . Frankly,
> I never thought of any of the openmath / math-sgml etc as dictating
> either storage formats, access efficiency, etc. Just an inefficient
> textual suggestion of what people might plausibly interpret the
> same way in spite of having different basic assumptions.

I often think of the columns of a matrix to be more important than the
rows.  Mainly this is due to the fact that e_i maps to the ith column of a
matrix.  So when I construct a matrix I likely know its column vectors
and not its row vectors.

This is refected when you see matrices written as:
     _                     _
    |     |     |     |     |
A = | V_1 | V_2 | ... | V_n |
    |_    |     |     |    _|

which is far more common that a row vector form.

This is where my thoughts of matrices alternately being defined by columns
comes from.  I don't know if there is time to put this idea into version
1.0 of MathML

-- 
Russell O'Connor                           roconnor@uwaterloo.ca
    <URL:http://www.undergrad.math.uwaterloo.ca/%7Eroconnor/>
"And truth irreversibly destroys the meaning of its own message"
-- Anindita Dutta, "The Paradox of Truth, the Truth of Entropy"
Received on Friday, 13 March 1998 23:17:56 GMT

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