Cfrgtkky

I get ! Undefined control sequence. l.11 forall n,m gt

I don't understand why:

documentclass[preview, border=1pt, convert={outext=.png}]{standalone}

usepackage{amsfonts}

usepackage{mathtools}

usepackage{amsmath,esint}

usepackage{amssymb}

usepackage{siunitx}

usepackage{braket}

usepackage[utf8]{inputenc}

begin{document}

begin{equation*}

forall n,m gt n_{varepsilon} quad Longrightarrow  quad ||mathbf{x}_n - mathbf{x}_m|| lt varepsilon

end{equation*}

end{document}

I think you are looking for ge and le. gt and lt are not defined.

documentclass[varwidth]{standalone}

usepackage{amsmath}

begin{document}

begin{equation*}

forall n,m ge n_{varepsilon} quad Longrightarrow  quad ||mathbf{x}_n - mathbf{x}_m|| le varepsilon

end{equation*}

end{document}

Edit 1

The > and < signs are already on your keyboard:

documentclass[varwidth]{standalone}

usepackage{amsmath}

begin{document}

begin{equation*}

forall n,m > n_{varepsilon} quad Longrightarrow  quad ||mathbf{x}_n - mathbf{x}_m|| < varepsilon

end{equation*}

end{document}

In case you want to use gt or lt, you have to define it. The definition below is taken from this answer:

documentclass[varwidth]{standalone}

usepackage{amsmath}

newcommand{lt}{symbol{"3C}}

newcommand{gt}{symbol{"3E}}

begin{document}

begin{equation*}

forall n,m lt n_{varepsilon} quad Longrightarrow  quad ||mathbf{x}_n - mathbf{x}_m|| gt varepsilon

end{equation*}

end{document}