Dear LyX documentators,
an addition to the LyX Math guide section
10.4 Self-defined Operators:
How to define a custom math operator in a Math-Macro?
\DeclareMathOperator{}{} sorgt für korrekte Abstände, aber kann nur in
der Preambel verwendet werden. Die Funktion \operatorname macht das
gleiche, aber geht auch im Document (und damit in Math-Makros)::
\begin_layout Standard
\begin_inset FormulaMacro
\renewcommand{\sgn}{\operatorname{sgn}}
{\textrm{sgn}}
\end_inset
\end_layout
\operatorname kann auch zur Umdefinierung von Befehlen verwendet werden
(\ReDeclareMathOperator gibt es nicht)::
Real- und Imaginärteil mit lateinischen Buchstaben à la ISO 31
\begin_inset FormulaMacro
\newcommand{\Re}{\operatorname{Re}}
{\mathrm{{\color{green}Re}}}
\end_inset
The difference between defining a command to be \operatorname{something}
and defining it by \DeclareMathOperator, is one level of macro expansion.
With the above definitions,
\Re --> operatorname{Re} --> [internal code for \operatorname{Re}]
\sgn --> [internal code for \operatorname{sgn}]
This is documented (amsldoc.pdf section 5, page 14).
One more suggestion (as the star variant is not confined to BIG
operators):
- To define a big operator a * is set behind the command. All self-defined
- big operators can have limits as described in [sub:Operator-Limits].
+ Operators defined with \DeclareMathOperator* can have limits as described
+ in [sub:Operator-Limits]. In Math-Macros use \operatorname*.
Günter
