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When I try to compile this simple document



I receive the following complaint:

! Undefined control sequence.
\it@comma@def  ->\futurelet \let@token
l.7 $\bm{,}

and a strange number (25915) is printed on the resulting pdf instead of the comma.
Something odd is going on with the babel package, because if I remove the line


everything works just fine.

Any thoughts?

share|improve this question
Welcome to TeX.SX! – egreg May 12 '14 at 9:17
up vote 6 down vote accepted

Unfortunately, the “intelligent comma” commands proposed in italian.ldf are not really smart.

You can avoid the problem with \bm by using




depending if you want it to be punctuation or an ordinary symbol.

share|improve this answer
Great answer, thank you! – Mizar May 12 '14 at 9:26

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