Possible Duplicate:
Blackboard bold characters
I have seen the unit (or identity operator) typeset via
\newcommand{\unit}{1\!\!1}
Is this really the best way to get a double-stroke 1? The obvious guess, \mathbb{1}
, does not work.
Or is the use of a double-stroke 1 (rather than "Id" or just a simple "1") for this purpose frowned upon?
\usepackage{bbm}
and\newcommand\idop{\bbm 1}
.