## LaTeX forum ⇒ Math & Science ⇒ Difference between ⫾ (U+2AFE) and ⫿ (U+2AFF)?

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user49915
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### Difference between ⫾ (U+2AFE) and ⫿ (U+2AFF)?

Continuing https://tex.stackexchange.com/questions ... d-language, what is the intended difference in the usage of ⫾ (Dijkstra choice, U+2AFE) and ⫿ (n-ary Dijkstra choice, U+2AFF)? Consider the following typesetting test:

\documentclass{article}\pagestyle{empty}\usepackage{mathtools}%%% loads amsmath internally\mathtoolsset{mathic=true} %%% See <!-- m --><a class="postlink" href="http://tex.stackexchange.com/a/3496/">http://tex.stackexchange.com/a/3496/</a><!-- m -->\usepackage{unicode-math}\setmainfont[Ligatures=TeX]{TeX Gyre Termes}\setsansfont{TeX Gyre Heros}[Scale=0.88]\setmonofont{TeX Gyre Cursor}%%% No explicit turning on ligatures for the monospaced font.%\setmathfont[Ligatures=TeX]{TeX Gyre Termes Math}%\setmathfont[Extension=.otf,Ligatures=TeX,range={"2AFE,"2AFF}]{STIXMath-Regular}\setmathfont{XITSMath-Regular.otf}\setlength{\tabbingsep}{0pt}%%% We use tabbing only to typeset programs. Let's have manual control there.\newcommand{\GCLcommand}[1]{\ifmmode\mathbfsf{#1}\else\textbf{\textsf{#1}}\fi}\newcommand{\mdoloop}{\GCLcommand{do}}\newcommand{\modloop}{\GCLcommand{od}}\newcommand{\mthen}{\ensuremath{\to}}\newcommand{\mif}{\GCLcommand{if}}\newcommand{\mfi}{\GCLcommand{fi}}\newcommand{\mnoop}{\GCLcommand{nop}}\begin{document}\newcommand{\test}{%\begin{tabbing}\mdoloop\=\ \ \=$$q_1>q_2$$ \ \=$$\to$$ \ \ \=\kill\mdoloop\>\>$$q_1>q_2$$\>\mthen\>$$q_1,q_2$$ $$\coloneqq$$ $$q_2,q_1$$\\\>\mchoice\'\>$$q_2>q_3$$\>\mthen\>$$q_2,q_3$$ $$\coloneqq$$ $$q_3,q_2$$\\\>\mchoice\'\>$$q_3>q_4$$\>\mthen\>$$q_3,q_4$$ $$\coloneqq$$ $$q_4,q_3$$\\\modloop\end{tabbing}Let$\mathit{DO}\ \ =\ \ \mdoloop\ \,\dots\ \mchoice\ G_i~ \mthen~ S_i\ \,\mchoice\,\ \dots\ \,\modloop$Then:$(\mathit{DO}, \sigma)\ \ \to\ \ (\mif\ \dots~ \mchoice ~G_i ~\mthen~ S_i; ~ \mathit{DO} ~\mchoice~ \dots \mchoice~ \neg (C_1 \land \dots \land C_n) ~\mthen~ \mnoop ~\mfi,~ \sigma)$where $C_i$ is the boolean expression in the guard of $G_i$ ($$1\le i\le n$$).%}%end of \test definition \newcommand{\mchoice}{\ensuremath{⫾}}\mchoice\ (U+2AFE):\test\\\hrule\bigskip\renewcommand{\mchoice}{\ensuremath{⫿}}\mchoice\ (U+2AFF):\test\end{document}

The output of xelatex demonstrates unexpectedly large size of ⫿ (U+2AFF) in \displaystyle:

file.png (230.09 KiB) Viewed 1487 times

Was Barbara's original answer https://tex.stackexchange.com/a/435995 (before the update) wrong, or am I typesetting anything in an unintended way?