# "! Missing \endcsname inserted.<to be read again>" for no particular reason

I was working on my LaTex skills regarding the output of diagrammatic algebra. I started well and soon got a grasp of tikz-cd package. I finished writing a fairly long construction and wanted to compile it (I'm using Texmaker). Here is the code:

\documentclass[a4paper]{report}

\usepackage{amsmath}
\usepackage{latexsym}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{amssymb}
\usepackage{amsxtra}
\usepackage{amscd}
\usepackage{amsopn}
\usepackage{lmodern}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{fullpage}
\usepackage{slashed}
\usepackage{mathtools}
\usepackage{microtype}
\usepackage{graphicx}
\usepackage{geometry}
\usepackage{mathdots}
\usepackage{mathrsfs}
\usepackage{tikz-cd}

\begin{document}

\setlength{\parindent}{0cm}

$\begin{tikzcd} 0 \arrow[r] & \mathcal{C}^{\infty , 0} \arrow[r, "\mathrm{grad}"] & \Lambda^{1,0} \arrow[r, "\mathrm{iot}"] & \Lambda^{1,-1} \arrow[r, "-\mathrm{div}"] & \mathcal{C}^{\infty , -3} \arrow[r] & 0 \\ 0 \arrow[r] & \Lambda^{1,2} \arrow[u, "X(\xi, \cdot)"] \arrow[r, "CK"] & \Sigma^{2,2} \arrow[u, "i(\xi; \cdot)"] \arrow[r, "\frac{1}{2}H"] & \Sigma^{2,-1} \arrow[u, "\xi \lrcorner \cdot"] \arrow[r, "-\mathrm{Div}"] & \Lambda^{1,-3} arrow[u, "\xi \lrcorner \cdot"] \arrow[r] & 0 \\ 0 \arrow[r] & \mathcal{C}^{\infty,0} \arrow[u, "\xi \otimes \cdot"] \arrow[r, "\mathrm{grad}"] & \Lambda^{1,0} \arrow[u, "\tau(\xi \otimes \cdot)"] \arrow[r, "\mathrm{iot}"] & \Lambda^{1,-1} \arrow[u, "BY(\xi ; \cdot)"] \arrow[r, "-\mathrm{div}"] & \mathcal{C}^{\infty, -3} \arrow[u, "j(\xi, \cdot)"] \arrow[r] & 0 \end{tikzcd}$

\end{document}


When I try to compile the code, the following error shows up:

! Missing \endcsname inserted.<to be read again>\cdot\end{tikzcd}


I'm absolutely desperate. I double-checked for mistakes in my code, I looked for the answer on different forums, but it was all in vain. Can someone please help me? I thank you (kind strangers) in advance.

• Welcome to TeX.SX! Feb 27 '17 at 17:12

## 1 Answer

You forgot one \ before arrow and sometimes forgot to surround , with { and } to prevent tikz from interpreting ,. Here is your code corrected so it compiles:

\documentclass[a4paper]{report}

\usepackage{amsmath}
\usepackage{latexsym}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{amssymb}
\usepackage{amsxtra}
\usepackage{amscd}
\usepackage{amsopn}
\usepackage{lmodern}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{fullpage}
\usepackage{slashed}
\usepackage{mathtools}
\usepackage{microtype}
\usepackage{graphicx}
\usepackage{geometry}
\usepackage{mathdots}
\usepackage{mathrsfs}
\usepackage{tikz-cd}

\begin{document}

\setlength{\parindent}{0cm}

$\begin{tikzcd} 0 \arrow[r] & \mathcal{C}^{\infty , 0} \arrow[r, "\mathrm{grad}"] & \Lambda^{1,0} \arrow[r, "\mathrm{iot}"] & \Lambda^{1,-1} \arrow[r, "-\mathrm{div}"] & \mathcal{C}^{\infty , -3} \arrow[r] & 0 \\ 0 \arrow[r] & \Lambda^{1,2} \arrow[u, "X(\xi{,} \cdot)"] \arrow[r, "CK"] & \Sigma^{2,2} \arrow[u, "i(\xi; \cdot)"] \arrow[r, "\frac{1}{2}H"] & \Sigma^{2,-1} \arrow[u, "\xi \lrcorner \cdot"] \arrow[r, "-\mathrm{Div}"] & \Lambda^{1,-3} \arrow[u, "\xi \lrcorner \cdot"] \arrow[r] & 0 \\ 0 \arrow[r] & \mathcal{C}^{\infty,0} \arrow[u, "\xi \otimes \cdot"] \arrow[r, "\mathrm{grad}"] & \Lambda^{1,0} \arrow[u, "\tau(\xi \otimes \cdot)"] \arrow[r, "\mathrm{iot}"] & \Lambda^{1,-1} \arrow[u, "BY(\xi ; \cdot)"] \arrow[r, "-\mathrm{div}"] & \mathcal{C}^{\infty, -3} \arrow[u, "j(\xi{,} \cdot)"] \arrow[r] & 0 \end{tikzcd}$

\end{document}

• Thank you so much! Latex community is the friendliest one for sure! Many thanks! Feb 27 '17 at 18:49