Double brackets

[Richard Kimberly Heck]

On 7/22/23 11:24, Dan wrote:
> I am trying to write a Lie bracket [[a, b ]].  The commands \llbracket 
> and \rrbracket work just fine in the LyX math formula, but doesn't 
> render in LuaTex.  I could conceivably use a negative space and join 
> the symbols | and [ (with some fussing) but I can't get LyX to 
> recognize \! as a negative spacer.  (That's another question, really.  
> I don't need that answered here if there is a simpler way to do this.)

Is there some reason that LuaTeX isn't recognizing these commands? I 
don't use it, so can't test, but they work fine with pdflatex. Is there 
some reason you need LuaTeX?

How are you entering \!? Directly in math mode? It works for me, but I'm 
using the 2.4 beta, so it could be a new thing (though I don't think so).

One workaround would be to define a command for this purpose in your 
preamble, then use it in math. It won't look pretty---you'll just see 
the bare command---but it will export properly.

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