On 16/01/2017 10:23, Andrew Parsloe wrote: > I'm not qualified to argue about the use of \mode_if_inner:TF beyond > saying that it has correctly worked to date. Any apparent correspondence between inner and outer math and displaystyle and textstyle is more or less accidental. Consider \documentclass{article} \usepackage{amsmath} \newcommand\test[1]{% \relax\ifinner\typeout{#1 inner}\else\typeout{#1 outer}\fi \sum_0^n } \begin{document} $\test{$}$ \[\test{[} \left(\test{[2}\right) \] \begin{eqnarray} \test{eqnarray} &=&0 \end{eqnarray} \begin{align} \test{align}&=1 \end{align} \end{document} all but the first sum is set in display math mode but all but the second have ifinner true. $ inner [ outer [2 inner eqnarray inner align inner align inner David ________________________________ The Numerical Algorithms Group Ltd is a company registered in England and Wales with company number 1249803. The registered office is: Wilkinson House, Jordan Hill Road, Oxford OX2 8DR, United Kingdom. This e-mail has been scanned for all viruses by Microsoft Office 365. ________________________________