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 Re: Distinguishing display styles in math mode Andrew Parsloe <[log in to unmask]> Tue, 17 Jan 2017 09:12:27 +1300 text/plain (39 lines) On 17/01/2017 12:00 a.m., Frank Mittelbach wrote: > Am 16.01.2017 um 11:41 schrieb David Carlisle: >> >> Any apparent correspondence between inner and outer math and >> displaystyle and textstyle is more or less accidental. > > > \ifinner is described in the TeXbook simply as > > True if \TeX\ is in internal vertical mode, or restricted > horizontal mode, or (nondisplay) math mode (see Chapter~13). > > which is unfortunately an over-simplification as the "style" can be > explicitly set via \displaystyle and \textstyle and that is not > reflected by the \ifinner test. > > Most math environment do exactly this, ie typesetting the formulas using > \$...\$ = \ifinner=true but changing the style to \displaystyle when > needed (with still \ifinner=true) which makes \ifinner pretty useless > inside math > > As Joseph said, that is really only reflected when you look at \mathchoice > Thank you to all respondents who have made it clear that "Math modes can be tested for: \ifmmode is true in display and non-display math mode, and \ifinner is true in non-display mode, but not in display mode" (Eijkhout, "TeX by Topic", Section 23.1) is by no means generally true. (Although I suspect that in the *particular* circumstances that I was using the \ifinner test it does the job.) Andrew --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus