Henry Baker <hbaker1@pipeline.com> wrote:

M F Hasler <mhasler@dsi972.fr> wrote:

...

any 2x2 matrix can be written as A = a? s? + *a* ? *?* *a* ? *?* = a? ?? + a? ?? + a? ?? where ?? = *I* is the identity matrix and *?* =* ? *= ( ?? , i ? , ?? ) are the three hermitian traceless Pauli matrices verifying ?? ?? = i ???? ?? where indices 123 can be replaced by any indices *i,j,k* and ? is the completely antisymmetric tensor with ???? = 1.

Sorry, I was unable to follow much of your post due to the fact that I'm still living in an ASCII world.

Thank you. I've pointed out several times that, at least for those of us on the digest option, any non-ASCII characters get turned into question marks. It's often possible to figure out from context that a specific question mark means pi or something, but much of the time, as above, it results in completely incomprehensible gibberish. But nobody listens to me. Maybe they'll listen to you.