Making systeme use superscripts

Question

I want to make a system of linear equations in LaTeX and I'm using systeme for that. The problem is that I want indices to be superscripted like this:

because that's the notation we use. Yet systeme uses bottom indexing and if I try to do that it gives an error:

\[
\systeme{x^1 + x^2 + x^3 = 1}
\]

Package systeme Error: l'inconnue "x_{-1}" a deja ete trouvee dans l'equation !.

Is there any workaround?

Answer 1

Use the command \syssubstitute (to be found in the systeme documentation), like this:

\documentclass{article}
\usepackage{systeme}
\begin{document}
\syssubstitute{{x_1}{x^1}{x_2}{x^2}{x_3}{x^3}}
\systeme{x_1 + x_2 + x_3 = 1}
\end{document}