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pellman
Jun28-09, 02:17 PM
I am coming across a notation in a math text whose form and context suggest it is something like a direct product. The symbol is a multiplication X with a vertical line connecting the two left side ends. Can someone identify this symbol please?

The context can be seen here http://books.google.com/books?id=3JXJ_o70imkC&pg=PA83&lpg=PA83&dq=folland+quantum+field+theory+tourists+%22this+w as+first+accomplished+by+wigner%22&source=bl&ots=hG-CCs2R-k&sig=l3x5V1kd-PrRec-GYxnKpLqrDlU&hl=en&ei=V7NHSs2yHYqONqCQrZcB&sa=X&oi=book_result&ct=result&resnum=1 2/3rds the way down on the page. This is an online preview of the text I am reading.

Hurkyl
Jun28-09, 02:29 PM
Maybe a semidirect product (http://en.wikipedia.org/wiki/Semidirect_product)?

pellman
Jun29-09, 06:44 AM
Hurkyl to the rescue again. That is it.

And look. The article lists the LaTex commands.
G = R^4 \ltimes SL(2,C)