On Mon, 10 Mar 2014, Sanjoy Mahajan wrote:
\hbar is used a lot in physics. Once in a while, one also uses \lambdabar to mean \lambda/2\pi. It's Unicode description is 'LATIN SMALL LETTER LAMBDA WITH STROKE' (U+019B).
I've been using this hack
\def\lambdabar{\lambda\kern-1ex\raise0.65ex\hbox{-}}
Is this the canonical name for the glyph used by AMS?
But it's not beautiful. Is there a better way to get a lambdabar into (or from) the math fonts? I tried
\def\lambdabar {\Umathchar "0"0"00019B }
by analogy with the definition of \hbar in luatex-math.tex,
The right way is to update char-def.lua as { adobename="lambdastroke", category="ll", description="LATIN SMALL LETTER LAMBDA WITH STROKE", direction="l", linebreak="al", mathclass="variable", mathname="lambdabar", unicodeslot=0x019B, },
but it produces a blank space. There must be no entry for it in the regular (or Palatino) math fonts.
The easiest solution will be to file a bug report with the TeX Gyre project. This is an easy glyph to add. Otherwise, you can use a different font as fall back for lambdabar, but that will not match the regular lambda from Palatino. If you create the glyph on your own, as in your definition above, then you have to play around with the length of the bar to make make it "pretty". Aditya