Accessing *all possible* math styles of the STIX font

Question

I have been using xelatex plus unicode-math for too long, and I forgot how to use pdflatex. As far as I heard, the STIX fonts are proposed as a free replacement of the fonts of Times family. They have a variety of styles and a large number of symbols. However, I recurrently fall in the same trap, namely, I do not know how to call different styles properly.

• Just today I've asked how to access the bold calligraphic style and got this excellent answer. I thought my problems were over, but then I discovered that \mathbfit as well as \bm does not produce bold slanted greek letters. I remember, I have see the solution already. There are also a lot of discussion here for different fonts.

• I found that last year I had a similar problem with STIX, and indeed got many useful answers. But then again, after re-reading the probably expert answer of Davislor I understood that I do not understand anything. Why it has to be sooooo difficult to make lambda bold!? Why, as a user, not developer I have to worry about the font ranges, fake bolds and isomath?

But I would like to narrow my question as much as possible in order to get a comprehensive answer. I would like to know how to access all possible 17 styles of math stix fonts and how this syntax is different from accessing all possible 9 styles of cm fonts. Furthermore, I am interested only in the pdflatex compatible answer. No font substitution is allowed.

Below is my minimal non working example

\documentclass[]{article}
\usepackage{stix}
\usepackage{amssymb,amsmath}
\newcommand{\symb}{aA\psi\Psi12}
\begin{document}
\begin{align}
%\mathup{\symb}\\
%\mathbfup{\symb}\\
\mathit{\symb}\\
\mathbfit{\symb}\\
%\mathsfup{\symb}\\
\mathsfit{\symb}\\
%\mathbfsfup{\symb}\\
\mathbfsfit{\symb}\\
\mathtt{\symb}\\
\mathbb{\symb}\\
\mathbbit{\symb}\\
\mathscr{\symb}\\
\mathbfscr{\symb}\\
\mathcal{\symb}\\
\mathbfcal{\symb}\\
\mathfrak{\symb}\\
\mathbffrak{\symb}
\end{align}
\end{document}

It gives me a strange error

! LaTeX Error: Too many math alphabets used in version normal.

Summary for making it a bountied question

1. My ultimate goal is to make as many as possible commands presented above to work in one document in a predictive fashion.

2. Naturally, no one will ever need to have all the styles in one document. So the error quoted above is not essential. But a reasonable subset of styles would be nice. An example would be in addition to regular variables, vectors (bold-italic, possibly calligraphic), matrices, tensors (bold serifless and sometimes calligraphic), sets (mathbb), codes (mathtt).

3. I would like an explanation why in order to use \mathbfcal (not even in the alphabet table) DeclareMathAlphabet is needed, whereas in order to use \mathbfit{\psi} for greek letters the option lcgreekalpha is needed. Especially for the latter, I was assuming that a font selection command is a low level command, unlike for instance \emph, which takes other considerations into account. But why then one needs lcgreekalpha to overwrite.

Answer 1

latex math alphabets (unlike math symbol fonts) are assigned on demand as they are used. This means that you can declare any number of math alphabets but you may only use a total of 16 math fonts (math symbol fonts and math alphabets). This 16 is a hard limit of the TeX program.

Apart from test documents that are trying to use every possible font in a single document it is highly unusual to need that many alphabets. So I am tempted to say that this is a feature.

If you really need to access that many fonts you can (with some constraints) declare the fonts as text fonts or (possibly better) declare different math versions (cf normal and bold math versions) and arrange that different subsets of the fonts are available in each version with no more than 16 in each.

That said the stix documentation answers your question and shows all the available math alphabet commands It also warns you that you can not use them all at once.

It is probably advisable to use the stix2 package (based on Stix Two Math font) but the commands are essentially the same and its documentation has essentially the same table.

---

Note that the hard limit of 16 math fonts is per version not per document, in your original example you have to comment out 3 math alphabet commands to keep below the limit but you can declare another math version with the same initial declarations but in which you use a different set of 16 so I could uncomment the final three math alphabets as long as I comment out some others.

\documentclass[]{article}
\DeclareMathVersion{normal2}
\usepackage{amsmath}
\usepackage[lcgreekalpha]{stix}
\DeclareMathAlphabet\mathbfcal{LS2}{stixcal}{b}{n}
\newcommand{\symb}{aA\psi\Psi12}
\begin{document}
\begin{align}
\mathrm{\symb}\\
\mathbf{\symb}\\
\mathit{\symb}\\
\mathbfit{\symb}\\
\mathsfit{\symb}\\
\mathbfsfit{\symb}\\
\mathtt{\symb}\\
\mathbb{\symb}\\
\mathbbit{\symb}\\
\mathscr{\symb}\\
\mathbfscr{\symb}\\
\mathcal{\symb}\\
\mathbfcal{\symb}\\
\mathfrak{\symb}\\
%\mathsf{\symb}\\
%\mathbfsf{\symb}\\
%\mathbffrak{\symb}
\end{align}
\mathversion{normal2}
\begin{align}
\mathrm{\symb}\
\mathbf{\symb}\
\mathit{\symb}\
\mathbfit{\symb}\
\mathsfit{\symb}\
\mathbfsfit{\symb}\
\mathtt{\symb}\
\mathbb{\symb}\
\mathbbit{\symb}\
\mathscr{\symb}\
%\mathbfscr{\symb}\
\mathcal{\symb}\
%\mathbfcal{\symb}\
%\mathfrak{\symb}\
\mathsf{\symb}\
\mathbfsf{\symb}\
\mathbffrak{\symb}
\end{align}
\end{document}

Note that some alphabets are not complete eg Fraktur doesn't have Greek not surprisingly so you get nonsense if switching to Fraktur for the Greek. Without the lcgreekalpha option the lowe case greek stays unstyled, but stays Greek: