Curly braces in Hasse diagram

Question

I need to create a Hasse diagram (i.e., lattice diagram) in LaTeX. Right now, I have the following code in tikz-cd.

\documentclass{standalone}

\usepackage{amsmath,tikz, tikz-cd}

\begin{document}
\begin{tikzpicture}[baseline= (a).base]
\node[scale=.85] (a) at (0,0){
\begin{tikzcd}[every arrow/.append style={dash}]
& & K_1 
\arrow[ddll]
\arrow[d]\\
& & k_1
    \arrow[ddll,sloped,pos=0.7,"\text{degree $p$}"]\\
K_0 \arrow[d,swap,"\text{degree 2} \, \,"] & & \\
k_0 & &
\end{tikzcd}
};
\end{tikzpicture}
\end{document}

I would like to add labeled vertical brackets to the diagram off to the side, preferably curly braces. For instance, I would like a vertical brace to the left of the diagram, labeled with 'H' and spanning from K_0 on the bottom to K_1 on the top. (Note: this is not the entire diagram -- the brace should extend down to K_0, not all the way down to k_0 at the bottom of the diagram.)

What is the simplest way to add these braces? Can I do it in tikz-cd? If not, what is the simplest alternative?

Bernard · Accepted Answer · 2017-06-19T00:12:28.380

5

I don't know how to add a brace emcompassing only part of the height of the figure with tikz, but it's easy to obtain it with pstricks:

\documentclass[border=3mm]{standalone}

\usepackage{amsmath, pstricks-add}
\usepackage{auto-pst-pdf}

\begin{document}
\psset{linejoin=1}
\everypsbox{\footnotesize}
$ \begin{psmatrix}[rowsep=1.3cm, colsep=2.5cm]
    \pnode[-4pt, 1.5ex]{K1}\phantom{K₁} & K₁ \\
    & k₁ \\
    \pnode[-4pt, -0.5ex]{K0}K₀ \\
    k₀
    \psset{nodesep=4pt, labelsep=2pt}
    \ncline{3,1}{1,2}\ncline{4,1}{2,2}\nbput[nrot=:U]{\text{degree $ p $}}
    \ncline{1,2}{2,2}\ncline{4,1}{3,1}\naput[nrot=:U]{\text{degree $ 2 $}}
    \psset{braceWidthInner=3pt,braceWidthOuter=3pt, braceWidth =0.8pt, nodesepB=-4pt, nodesepA=-1pt}
    \psbrace(K1)(K0){H}
  \end{psmatrix} $

\end{document}

edited Jun 19 '17 at 00:12

answered Jun 18 '17 at 22:25

Bernard

271,350

It doesn't look that easy, since I don't know pstricks! But I'll try to learn enough to figure out what you did. Thanks. – Barry Jun 19 '17 at 21:26
It's much easier to learn than TikZ, because it uses a LaTeX syntax, and it's well documented (by modules, no more than 130 pages each time). – Bernard Jun 19 '17 at 21:30
@Barry: If you want to understand what happens, take a look at the documentation of pst-node , and especially § 7, Mathematical diagrams and graphs, pp. 21–23. – Bernard Jun 19 '17 at 21:49

score 4 · Answer 2 · answered Jun 18 '17 at 14:35

A simple cases environment will do:

\documentclass[border=3mm]{standalone}

\usepackage{amsmath, tikz, tikz-cd}

\begin{document}

$ H \begin{cases}
    \begin{tikzpicture}[baseline= (a).base]
      \node[scale=.85] (a) at (0,0){
        \begin{tikzcd}[every arrow/.append style={dash}]
          & & K_1
          \arrow[ddll]
          \arrow[d]\\
          & & k_1
          \arrow[ddll,sloped,pos=0.7,"\text{degree $p$}"]\\
          K_0 \arrow[d,swap,"\text{degree 2} \, \,"] & & \\
          k_0 & &
        \end{tikzcd}
      };
    \end{tikzpicture}
  \end{cases} $

\end{document}

This extends all the way to the bottom of the diagram, which I don't want. Perhaps the capitalization in my OP made it unclear. I have updated the OP to make clear that the brace should extend only partway down. — Barry, Jun 18 '17 at 18:37

score 3 · Answer 3 · answered Jun 18 '17 at 13:30

With \left\lbrace and \right.

\documentclass[border=3mm]{standalone}

\usepackage{amsmath,tikz, tikz-cd}

\begin{document}
$H \left\lbrace 
    \begin{tikzpicture}[baseline= (a).base]
    \node[scale=.85] (a) at (0,0){
        \begin{tikzcd}[every arrow/.append style={dash}]
        & & K_1 
        \arrow[ddll]
        \arrow[d]\\
        & & k_1
        \arrow[ddll,sloped,pos=0.7,"\text{degree $p$}"]\\
        K_0 \arrow[d,swap,"\text{degree 2} \, \,"] & & \\
        k_0 & &
        \end{tikzcd}
    };
    \end{tikzpicture}
\right.$    
\end{document}

This extends all the way to the bottom of the diagram, which I don't want. Perhaps the capitalization in my OP made it unclear. I have updated the OP to make clear that the brace should extend only partway down. — Barry, Jun 18 '17 at 18:37

Hotschke · Answer 4 · 2019-02-26T10:38:24.700

A solution for tikz-cd using decorations.pathreplacing

\documentclass{standalone}

\usepackage{amsmath,tikz}
\usetikzlibrary{cd,decorations.pathreplacing}

\begin{document}
\begin{tikzcd}[every arrow/.append style={dash}]
    \vphantom{K_1} \arrow[dd, start anchor=north, end anchor=south, no head, xshift=-1em, decorate, decoration={brace,mirror}, "H" left=3pt] & & K_1 \arrow[ddll] \arrow[d]\\
    & & k_1 \arrow[ddll,sloped,pos=0.7,"\text{degree $p$}"]\\
    K_0 
        \arrow[d,swap,"\text{degree 2} \, \,"] & & \\
    k_0 & &
\end{tikzcd}
\end{document}

Note \vphantom{K_1} to ensure that the anchor north is at the correct place.

Following answers of other questions were helpful

How to insert a big brace, arrows crossing etc
Problems with tikzcd diagrams (BTW title of this question is too generic.)
Overhead brace in tikz
Horizontal and vertical braces below and next to a tabular table
tikz-cd: Error: No shape named tikz@f@1-0-1 found (place {} to draw an arrow to an empty cell)

and also following weblink

https://spartanideas.msu.edu/2018/05/23/grouping-rows-of-a-matrix/

Perfect, thanks so much for adding these even two years after the question had been answered! My application needed a horizontal brace, and the key line was \arrow[rrr, start anchor=west, end anchor=east, no head, yshift=1em, decorate, decoration={brace}, "T" above=3pt]. — Joshua P. Swanson, Dec 02 '22 at 00:10

Curly braces in Hasse diagram

4 Answers4