[XeTeX] Jump symbol in latex

[José Miguel Figueroa-O'Farrill]

On 23 Jan 2008, at 13:22, Yaniv Hollander wrote:

> Hello,
>
> I need a help with finding the command that will produce a jump  
> symbol in Latex.
> A jump symbol looks like this: '[[', ']]'.
> Latex provides the command \lVert and \rVert for the symbol '||'. I  
> need two left brace and right brace commands the will produce the  
> same thing but with '[[' or ']]' instead of '||'.
>
> Thanks,
>
>
> Yaniv                       Hollander
> yaniv.hollander at gmail.com
>

I have never come across this character in the fonts I know.   
Whenever I have had to use it I have defined something like

\newcommand{\lJump}{[\![}
\newcommand{\rJump}{]\!]}

It's perhaps not ideal, but it worked for me.

Cheers, José




Prof José Figueroa-O'Farrill
School of Mathematics
University of Edinburgh