Hi,
That's true, it's better with a little bit of code. But the file is large and I didn't know what to show.

##################################################################################################
\protected\def\coord#1#2#3{\math{#1\left(#2\,;#3\right)}}
\starttext
\im{\mtext{E\timesF}=\big\{\coord{a}{1}\,;\coord{a}{2}\,;\coord{b}{1}\,;\coord{b}{2}\,;\coord{c}{1}\,;\coord{c}{2}\big\}},
             
and \im{\mtext{F\times E}=\big\{\coord{1}{a}\,;\coord{2}{a}\,;\coord{1}{b}\,;\coord{2}{b}\,;\coord{1}{c}\,;\coord{2}{c}\big\}}.
\stoptext

##################################################################################################

Le sam. 15 mars 2025 à 12:34, Mikael Sundqvist <mickep@gmail.com> a écrit :
Hi,

On Sat, Mar 15, 2025 at 12:05 PM Fabrice Couvreur
<fabrice1.couvreur@gmail.com> wrote:
>
> Hi,
> I just updated lmtx, and a file that compiled without errors is now returning errors. I don't know why.
> Thanks
> Fabrice
>
>
> tex error       > tex error on line 132 in file ./chapter-5.tex: Missing \right\nomathchar inserted
>
> <to be read again>
>
>     \Ustopmathmode
> <macro> \im
>     #1->\relax \ifmmode \mathconstruct {\textstyle \indisplaymath \conditionalfalse #1}\else \Ustartmathmode \textstyle \indisplaymath \conditionalfalse \expand \everyinsidemathematics \relax #1\Ustopmathmode
>     \fi
> <line 3.132>
>                  Alors \im{\text{E\times F}=\big\{\coord{a}{1}\,;\coord{a}{2}\,;\coord{b}{1}\,;\coord{b}{2}\,;\coord{c}{1}\,;\coord{c}{2}\big\}}
>     ,
>
> 122
> 123               En d'autres termes, nous avons
> 124               \startformula
> 125                 A\times B=\bigg\{\left(a, b\right)/ a\in A, b\in B\bigg\}.
> 126               \stopformula
> 127             \stopDefinition
> 128             \startexemples
> 129               \starttest
> 130                  Soient \m{\text{E}=\big\{a\,;b\,;c\big\}} et \m{\text{F}=\big\{1\,;2\big\}}.
> 131
> 132 >>               Alors \im{\text{E\times F}=\big\{\coord{a}{1}\,;\coord{a}{2}\,;\coord{b}{1}\,;\coord{b}{2}\,;\coord{c}{1}\,;\coord{c}{2}\big\}},
> 133
> 134             et \im{\text{F\times E}=\big\{\coord{1}{a}\,;\coord{2}{a}\,;\coord{1}{b}\,;\coord{2}{b}\,;\coord{1}{c}\,;\coord{2}{c}\big\}}.
> 135           \stoptest
> 136               \starttest
> 137                 Soient \m{A=\N} et \m{B=\big\{0\,;1\big\}}. Nous avons
> 138                 \startformula
> 139                   \N\times \big\{0\,;1\big\}=\big\{\left(n, b\right)\,\text{tels que}\,n\in \N, b\in \big\{0\,;1\big\} \big\}=\big\{(n, 0)/n\in \N\big\}\cup \big\{(n, 1)/n\in \N\big\},
> 140                 \stopformula
> 141                 ce qui donne
> 142                 \startformula
> I've inserted something that you may have forgotten. (See the <inserted text>
> above.) With luck, this will get me unwedged.
> mtx-context     | fatal error: return code: 1
>
> TeX Output exited abnormally with code 1 at Sat Mar 15 11:57:16
> ___________________________________________________________________________________
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Not easy without a small complete file to test. But the first thing I
noticed was \im {\text{E\times F}}. That seems conceptually wrong, and
the \times inside the \text is not done in math mode. But as Wolfram
just wrote, please make a small test file showing also the definition
of \coord.

/Mikael

PS \mtext is preferred over \text for text in math.
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl
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___________________________________________________________________________________