Loading symbol from mathb font does not work when document class is amsart

Question

In this question I found out how to load a "double prec" as a single symbol.

For some reason, this code does not work when the documentclass is

\documentclass[11pt,a4paper]{amsart}

Minimal non-working example:

\documentclass[11pt,a4paper]{amsart}
\pagestyle{plain}

\DeclareFontFamily{U}{mathb}{\hyphenchar\font45}
\DeclareFontShape{U}{mathb}{m}{n}{
<-6> mathab <6-7> mathb6 <7-8> mathb7
<8-9> mathb8 <9-10> mathb9
<10-12> mathb10 <12-> mathb12
}{}
\DeclareSymbolFont{mathb}{U}{mathb}{m}{n}
\DeclareMathSymbol{\llcurly}{\mathrel}{mathb}{"CE}
\DeclareMathSymbol{\ggcurly}{\mathrel}{mathb}{"CF}

\def\blueDiamond{\mathbin{\color{SteelBlue3}\blacklozenge}}

\begin{document}
\[ a \llcurly b \quad a \ggcurly b \]
\end{document}

I get the following output:

...

("C:\Program Files (x86)\MiKTeX 2.9\tex\latex\amsfonts\umsb.fd")Running miktex-makemf.exe... miktex-makemf: The mathab source file could not be found.

Running hbf2gf.exe...

hbf2gf (CJK ver. 4.8.3)

Couldn't find `math.cfg'

miktex-maketfm: No creation rule for font mathab.

! Font U/mathb/m/n/5=mathab at 5.0pt not loadable: Metric (TFM) file not found. relax l.21 \begin{document}

?

If I change the documentclass line to

\documentclass[11pt,a4paper]{article}

then PDF is generated successfully (with the following output):

...

Running miktex-mf.exe...

This is METAFONT, Version 2.718281 (MiKTeX 2.9)

...

Font metrics written on mathb10.tfm.

Output written on mathb10.300gf (250 characters, 26804 bytes).

Transcript written on mathb10.log.

METAFONT failed for some reason

ignoring 0 strange path(s)

[1{C:/ProgramData/MiKTeX/2.9/pdftex/conf ig/pdftex.map}] (C:\temp\artikkel_doubleprec_test.aux)Trying to make PK font mathb10 at 657 DPI...

Creating mathb10.pk...

Running miktex-mf.exe...

This is METAFONT, Version 2.718281 (MiKTeX 2.9)

...

Why does it not work with document class amsart?

Answer 1

The smallest font should be mathb5 not mathb (error in the original but not triggered in the original document)

\documentclass[11pt,a4paper]{amsart}
\pagestyle{plain}

\DeclareFontFamily{U}{mathb}{\hyphenchar\font45}
\DeclareFontShape{U}{mathb}{m}{n}{
<-6> mathb5 <6-7> mathb6 <7-8> mathb7
<8-9> mathb8 <9-10> mathb9
<10-12> mathb10 <12-> mathb12
}{}
\DeclareSymbolFont{mathb}{U}{mathb}{m}{n}
\DeclareMathSymbol{\llcurly}{\mathrel}{mathb}{"CE}
\DeclareMathSymbol{\ggcurly}{\mathrel}{mathb}{"CF}

\def\blueDiamond{\mathbin{\color{SteelBlue3}\blacklozenge}}

\begin{document}
\[ a \llcurly b \quad a \ggcurly b \]
\end{document}