\documentclass{article} \newcommand{\Lbrack}[2]{#1\brack #2} \newcommand{\Lbrace}[2]{#1\brace #2} \begin{document}\noindent The bracket structures in text formulas: $\Lbrack{n+1}{m-1}$, $\Lbrace{n+1}{m-1}$ \noindent The bracket struktures in displayed formulls: \[ \Lbrack{n+1}{m} \] \[ \Lbrace{n+1}{m-1} \] \end{document}