# Diagram of field theory

I want to write this picture in LaTeX, what is the code?

• Please show what you've tried... Can you do that? – Werner Oct 21 at 18:45
• you are really mis-using this site, you can not keep posting pictures and asking people to code them for you. Try coding them and if you get a tex error post your code and ask for tex help – David Carlisle Oct 21 at 18:46

Using tikz:

\documentclass[border=2mm]{standalone}
\usepackage{tikz}
\usepackage{amssymb}

\begin{document}

\begin{tikzpicture}

\node (Q1) at (0,0) {$\mathbb{Q}$};
\node (Q2) at (2,2) {$\mathbb{Q}\Big[\sqrt{2}\Big]$};
\node (Q3) at (0,4) {$\mathbb{Q}\Big[\sqrt[3]{2} \, ; \sqrt{2}\Big]$};
\node (Q4) at (-2,2) {$\mathbb{Q}\Big[\sqrt[3]{2}\Big]$};

\draw (Q1)--(Q2) node [pos=0.7, below,inner sep=0.25cm] {2};
\draw (Q1)--(Q4) node [pos=0.7, below,inner sep=0.25cm] {3};
\draw (Q3)--(Q4);
\draw (Q2)--(Q3);
\draw (Q1)--(Q3);

\end{tikzpicture}

\end{document}

• Welcome back and I'm happy :-) You have my approval for your answer given. – Sebastiano Oct 21 at 19:11

I use instead....xy package... to draw the image of the user. I put a screenshot of my MWE.

\documentclass[12pt]{article}
\usepackage{amsmath,amssymb}
\usepackage[all]{xy}

\begin{document}

$\xymatrix@R+1.5pc@C-0.3pc{ &\mathbb{Q}[\sqrt[3]{2};\sqrt{2}]\ar@{-}[ld]\ar@{-}[rd] \ar@{-}[dd]\\ \mathbb{Q}[\sqrt[3]{2}] \ar@{-}[rd]_3 &&\mathbb{Q}[\sqrt{2}]\ar@{-}[ld]^2\\ & \mathbb{Q} & }$
\end{document}


The lines are straight and is only an optical effect of the Papeeria display.

• @down-voter: What is the reason, please, of the downvote for me, Zarko and Milo? – Sebastiano Oct 21 at 20:20
• One reason could be that if you downvote three times you are harder to spot. Downvoting at the beginning of the week is dangerous since you can be identified rather easily unless you take some precautions. (Needless to say that it wasn't me.) – Schrödinger's cat Oct 21 at 21:32

With use of the tikzcd package:

\documentclass[border=32mm]{standalone}
\usepackage{amssymb}
\usepackage{tikz-cd}

\begin{document}
\begin{tikzcd}[row sep=huge]
& \mathbb{Q}\Bigl[\sqrt[3]{2} \, ; \sqrt{2}\Bigr]
\ar[dl,-]\ar[dd,-]\ar[dr,-]     &                          \\
\mathbb{Q}\Bigl[\sqrt[3]{2}\Bigr]\ar[dr,"3" ',-]
&                           & \mathbb{Q}\Bigl[\sqrt{2}\Bigr]
\ar[dl,"2",-]               \\
& \mathbb{Q}                &
\end{tikzcd}
\end{document}


With tikz-cd:

\documentclass{article}
\usepackage{tikz, tikz-cd}
\usepackage{amssymb}

\begin{document}

\begin{tikzcd}[arrows=dash, row sep=3.5em, column sep=1.5em]
& \mathbb{Q}\Bigl[\sqrt[3]{2},\sqrt{2}\Bigr] \dlar\arrow[dd] \drar\\
\mathbb{Q}\Bigl[\sqrt[3]{2}\Bigr] \drar["\textstyle 3",swap]& & \mathbb{Q}\Bigl[\sqrt{2}\Bigr]\dlar["\textstyle 2"]\\
& \mathbb{Q}
\end{tikzcd}

\end{document}