Compiling this code
\documentclass[a4paper,12pt,twoside]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[ngerman,english]{babel}
%MATHEMATICS
\usepackage{mathbbol}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsthm}
\usepackage{tikz-cd}
\begin{document}
\begin{center}
\begin{tikzcd}[column sep=huge]
F(X) \arrow[r,"F(X)"]\arrow[d,"F(X)"]&F(X)\arrow[d,"F(X)"]\\
F(X)\arrow[r,"X^{{\mathcal D}}_{F(X),F(Y)}"]&F(X)
\end{tikzcd}
\end{center}
\end{document}
I got the error 'Undefined controll sequence \end{tikzcd}'. And the reuslt looks not good at all. How can I fix that problem?
\usetikzlibrary{babel}after\usepackage{tikz-cd}. – Jul 29 '18 at 16:56tikzlibrarybabelsolve the problem. – Zarko Jul 29 '18 at 19:04