In the unicode-math package, what is the difference between \mupalpha and \upalpha? What is the purpose of the m prefix?
1 Answer
Sorry for the slow reply :)
This might not be documented particularly well. \mupalpha refers to an input character, and \upalpha essentially refers to an output character (which is usually what a user is interested in).
If you take a look in unicode-math-table.tex you see that \mupalpha is listed as the definition for the mathematical upright alpha:
\UnicodeMathSymbol{"003B1}{\mupalpha }{\mathalpha}{small alpha, greek}%
If you then write \show\mupalpha in a document you will receive (at time of writing, this might change in the future):
> \mupalpha=the character α.
The upright/italic nature of Greek symbols in the OUTPUT is controlled by unicode-math options like math-style=upright. I.e., writing
\documentclass{article}
\usepackage[math-style=french]{unicode-math}
\begin{document}
$\mupalpha$ or $α$
\end{document}
will result in two upright alphas — the two input forms (command or char) are equivalent.
In contrast, \upalpha is a long-standing LaTeX command to produce, you guessed it, an upright alpha. In fact, it is defined internally as \symup{\alpha}. So regardless of math-style and so on, writing \upalpha will ALWAYS give you an upright alpha.
\upalphaor\mupalphain the user guide of theunicode-mathpackage. In contrast,\mupalphais mentioned in the user guide of the unimath-symbols package. Is that maybe the package you're thinking of?unicode-mathpackage website provides the document "List of symbols defined by the package". This document lists\mupalpha, but not\upalpha. Both symbols work in XeTex.unimath-symbolspackage. :-) I'd say that\mis a generic prefix for math-symbols; the following variant glyphs of\alphaare defined:\mupalpha,\mitalpha,\mbfalpha,\mbfitalpha,\mbfsansalpha, and `\mbfitsansalpha. However, not all math fonts provide all of these glyph variants. The various TeX formats (Plain, LaTeX, etc) may provide additional macros that point directly to these glyphs.