# \leqslant causes “Undefined control sequence”

I have the following line: $0 \leqslant b \leqslant 1$

I want to display 0 <= b <= 1, but I get Undefined control sequence

thanks

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Are you loading the amssymb package? –  Gonzalo Medina Apr 25 '11 at 16:42

do you want it like this way? $0 \le b \le 1$. Otherwise load \usepackage{amssymb}

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You should use the amssymb package.

\documentclass{minimal}
\usepackage{amssymb}
\begin{document}
$0 \leqslant b \leqslant 1$
\end{document}

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