# Cases environment with SIAM document class

It seems as though the SIAM class does not play nice with the cases environment. For example

$$\begin{cases} x & y \end{cases}$$


will produce the error

misplaced alignment tab character


Oddly enough,

$$\begin{cases} x \\ y \end{cases}$$


compiles, but puts x and y on the same line.

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cases environment is defined in amsmath so you presumably want \usepackage{amsmath} otherwise you get the original (more or less undocumented) \cases command that is defined in latex but really comes from plain tex and should not be used – David Carlisle Jan 10 '14 at 0:05
Thanks. If you put your answer here I can accept it thereby closing the question. – par Jan 10 '14 at 0:13

The cases environment is defined in amsmath so you presumably want

\usepackage{amsmath}


otherwise you get the original (more or less undocumented) \cases command that is defined in latex but really comes from plain tex and should not be used.

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you might also have suggested using $...$ instead of $$...$$. – barbara beeton Jan 10 '14 at 14:39
@barbarabeeton I thought about it, but one thing at a time:-) – David Carlisle Jan 10 '14 at 14:42