# How can I see definition of an existing math symbol?

I want to create a symbol similar to \doublebarwedge from the package mathabx, with the wedge replaced by a triangle. Since I want to use both symbols, they should be as similar as possible (regarding size, height, spacing etc.). This is why I would like to see how the symbol \doublebarwedge is defined. I couldn't find anything in the package documentation.

This is not a duplicate: see the comment by David Charlisle below.

• it's like asking how to see the definition of "g" it is not something defined in tex it is something constructed by the font designer. – David Carlisle Dec 14 '17 at 7:51
• Possible duplicate of Display source for a command – Alex Recuenco Dec 14 '17 at 8:01
• @AlexRecuenco It's not really a duplicate, you would find out there that it's \doublebarwedge=\mathchar"255A but that doesn't answer the question here of how to see how big the wedge is to make a matching triangle – David Carlisle Dec 14 '17 at 8:05
• @David, seeing his response to jknappen wonderful answer, I think that is what Larry was looking for. Since, after seeing that it was a font character, he understood that it was out of his reach. Which he would have seen immediately if he had simply typed \show\doublebarwedge – Alex Recuenco Dec 14 '17 at 9:06

The mathabx fonts are distributed with METAFONT source code. The relevant source for the double bar wedge sign is found in the file mathabx/source/mathltkl.mf and reads:

beginchar(wedge_eqq,12u#+2appr#,asc_height#,0);% strange choice
"Wedge-equal sign";
pickup tiny.nib;
top y2r=x_height; bot y1r=0; y1r=y1l=y3r=y3l;
x2r=good.x 0.5w;
x3r-x2r=x2r-x1r=hround((y2r-y1r+o)/sqrt3);% see wedge sign (+o)
x1l-x1r=diag_width(rth-tiny,z2r-z1r);
x3r-x3l=diag_width(rth-tiny,z2r-z3r);
z2l-z1l=whatever*(z2r-z1r); z2l-z3l=whatever*(z2r-z3r);
pos4(rth,90); pos5(rth,90); pos6(rth,90); pos7(rth,90);