Last modified: 2013-11-04 10:31:15 UTC
While "\:" is a perfectly valid spacing command in TeX, it fails in <math>-Environment when using PNG-rendering. MathJax on the o Failing with PNG, but perfectly ok with MathJax: <math>U= 10^{-3} R\:I\qquad\textrm{mit }[U]=\mathrm{kV}, [R]=\mathrm{\Omega}, [I]=\mathrm{A}</math> Working in both variants: <math>U= 10^{-3} R\cdot I\qquad\textrm{mit }[U]=\mathrm{kV}, [R]=\mathrm{\Omega}, [I]=\mathrm{A}</math> Since \: is perfectly valid TeX-syntax as presented above, the PNG-renderer should be fixed accordingly.
It's tex but not texvc. So it produces an lexical error as it is supposed to do. That it works with MathJax is a bug. You can submit a feature request for expanding the texvc grammar with the \: command.
How can that be a bug within MathJax? They define their goal as being LaTeX-compatible, and the spacing command in question actually _is_ valid. Since texvc also states (at least on any describing Wiki-Page (en, de etc.) to be aiming to TeX compatibility, why should this be no bug in texvc?
MathJax defined a custom style for the texvc language. MathJax should support every command defined by texvc and not allow all commands that are not whitelisted by texvc. The texvc language is formally defined in the code only. And this code does not contain the command name ":". I think thats not very good and I think it has to be changed in the future to have a customizable language and a process for adding and removing commands. But before we can come up with customized commands the checking part of texvc has to be separated from the conversion part. I did that, but the code was not yet merged, and is waiting for code review. For a list of commands see http://www.formulasearchengine.com/texvc-light If you want to contribute on that you can help reviewing the texvc code... I wrote a little guide how to verify the code: http://www.formulasearchengine.com/Verify%20texvc%20light
