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% a multirelation of a simple equality between variables
\[ a=b=c \]
% incomplete multirelation, typically due to alignments
\[ y<2< \]
% inequality
\[ 1 \leq l < j \leq n \]
% list of inequalities
\[ 1<x<10, 2<y<20, 3<z<30\]
% approximation
\[ a,b ~ \alpha + \frac{1}{\alpha}\]
\end{document}