I was wondering what was the cause of the following warning message with the specific \usepackage used below:

Using the following:



Warning message

Package amsmath Warning: Foreign command \atopwithdelims;
(amsmath)                \frac or \genfrac should be used instead
(amsmath)                 on input line 56.

Line 56

\[ \frac{gcd(m,n)}{n} {n\choose m} \] is an integer for all pairs of integers $n\geq m\geq 1$.


1 Answer 1


\atopwithdelims is a TeX math primitive command. If you use amsmath, you don't need \atopwithdelims or \atop, use amsmath macros such as \frac, \binom, \genfrac etc. instead.

If a class or package uses this command, or a command such as \choose which uses it, you would get this warning. I would ignore the warning then, otherwise I would have to redefine the concerned macros of the package or class.

Alternatively, I suggest that you use \binom{a}{n}.

  • Thanks, that is exactly what it is. Using the \choose command for the binomial coefficients. So you suggest ignoring the warning since I am using the \choose ?
    – night owl
    Jun 1, 2011 at 12:13
  • 34
    @night owl: I suggest using \binom{a}{b} instead of {a \choose b}.
    – Stefan Kottwitz
    Jun 1, 2011 at 12:30
  • 7
    @StefanKottwitz Given that you use \choose as an example, would you consider moving the use of \binom{n}{m} into your answer? I suspect many people find their way to this question when using \choose. Dec 23, 2017 at 5:06

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