# pmatrix without changing font size

In Plain TeX with the amstex package, is there a way to tell \pmatrix to NOT change font size?

E.g. when I do:

\sum_{\pmatrix a \\ b \\ c \endpmatrix}


I end up having to insert \scriptstyle three times in front of the a, the b, and the c.

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You can use \everymath={\scriptstyle} to change to \scriptstyle

$\sum_{\everymath={\scriptstyle} \pmatrix {a \cr b \cr c }}$ (With scriptstyle)

\bigskip
$\sum_{\pmatrix {a \cr b \cr c }}$  (Without scriptstyle)

\bye


Note that the \everymath={\scriptstyle} \ is within a {} group and hence its effect are local to that group.

Also, I am not a TeX expert, and could not get your syntax to compile as your provided, so had to adapt it, so if this does not work for you, please provide a full MWE.

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there's a \smallmatrix meant for use in text; it sets the baselines closer together as well as making the letters smaller. (in @Peter's example, the baselines don't change, so the letters are equally far apart even though they are different sizes.) you do have to include the parentheses yourself:

$\sum_{\left(\smallmatrix a \\ b \\ c \endsmallmatrix\right)}$

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