Dr. Olaf Hoffmann wrote: > David Woolley: > >> Can you provide a concrete example. I would have thought that, if the >> inverse didn't exist, there will always be points that don't have a >> unique image when the transform is reversed. > > > If the determinant of the transformation matrix is zero, > 2-dimensional and 1-dimensional structures are mapped > to 1-dimensional structures or points. Just looking at the > result, it is not possible to reverse such transformation, > it is not a bijective function, just surjective. That was my point. There is no way of inverting the transform, even if one works with the individual steps, not just the matrix. -- David Woolley Emails are not formal business letters, whatever businesses may want. RFC1855 says there should be an address here, but, in a world of spam, that is no longer good advice, as archive address hiding may not work.Received on Sunday, 28 September 2008 17:41:33 GMT
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