I've corrected and updated my Dictionary entry

for "transformation":

http://www.ixpres.com/interval/dict/transform.htm

I'd appreciate errata, criticism, etc.,

before I post an announcement on the big list.

In particular:

- is is correct to use the word "translation"?

(at the beginning of the definition)

- When I look at the final (bottom) diagram on the

"transformation" webpage (the one that has the d,q

unit-vectors divided into 1/7ths), my spatial imagination

tells me that the correct algebraic solution is:

x = (di + cj) / n

y = (bi + aj) / n

I can see by looking at the diagram that this is

the way the coordinates transpose according to the

matrix determinant, in a sort of criss-cross pattern.

But the formula I derive (about 1/5 of the way down

the page) is

x = (di - bj) / n

y = (aj - ci) / n

They're not the same. ... ?

Is the first set correct generally, or only for this

particular example? Or is it the second set that's

only correct in this particular example?

-monz

_________________________________________________________

Do You Yahoo!?

Get your free @yahoo.com address at http://mail.yahoo.com