wrote:

A better phrase might be "self-similar" transformation.
I believe these are part of the relativity theorists'
armoury [...]

Me yet again (sorry). In case anyone is interested,
here's what looks like an excellent reference for this:


http://users.math.uni-potsdam.de/~oe...S/selfsim1.htm

"Self-similarity in general relativity";
B J Carr and A A Coley;
1999