How to write inclusion symbols diagonally?

Question

I have two sequences of inclusions, say $A \subset B \subset C$ and $A \subset D \subset C$, and I want to combine these into one sequence. I don't know how to explain this very well, but the combined sequence should look like "a diamond" of inclusions. How can I do this in LaTeX?

EDIT: What I have in mind is something like this:

Answer 1

For example (some spacing correction may be needed):

\documentclass{article}
\usepackage{graphicx}

\begin{document}

\[
\rotatebox{45}{$
\begin{array}{ccc}
\rotatebox{-45}{$A$} & \subseteq & \rotatebox{-45}{$B$} \\
\rotatebox{-90}{$\subseteq$}& &\rotatebox{-90}{$\subseteq$}\\[9pt]
\rotatebox{-45}{$C$} & \subseteq &\rotatebox{-45}{$ D$}
\end{array}
$}
\]

\end{document}

Answer 2

Maybe too many features, but whenever it's possible to simplify input, it's better doing it.

\documentclass{article}
\usepackage{amsmath,graphicx,xparse}

\NewDocumentCommand{\diamondinclusion}{m >{\SplitArgument{1}{\\}}m m}
 {%
  \dodiamondinclusion{#1}#2{#3}%
 }
\NewDocumentCommand{\dodiamondinclusion}{mmmm}
 {%
  \begingroup
  \setlength{\arraycolsep}{0pt}%
  \renewcommand{\arraystretch}{-2}%
  \begin{matrix}
  && #2 \\
  & \rsubseteq{45} && \rsubseteq{-45} \\
  #1 &&&& #4 \\
  & \rsubseteq{-45} && \rsubseteq{45} \\
  && #3
  \end{matrix}%
  \endgroup
 }
\NewDocumentCommand{\rsubseteq}{m}
 {%
  \rotatebox[origin=c]{#1}{$\subseteq$}%
 }

\begin{document}
\[
\diamondinclusion{A}{B\\C}{D}
\]
\end{document}

Just modify the definition of \dodiamondinc if you need changes.

Answer 3

A solution that uses pstricks and the psmatrix environment from pst-node. It is compilable with pdflatex if you set the --enable-write18 (MiKTeX) or --shell-escape (TeXLive, MacTeX).

 \documentclass[a4paper,11pt, pdf]{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}%
\usepackage{lmodern}

\usepackage{pst-node}


\newpsobject{ncemptyline}{ncline}{linestyle=none}
\newcommand*\ncsubset[2]{\ncemptyline{#1}{#2}\ncput[nrot=:U, npos=0.45]{\subset}}

\pagestyle{empty}

\begin{document}

\[ \begin{psmatrix}[rowsep=0.4, colsep=0.5]
 & [name = C] C \\
[name = B] B & & [name = D] D \\
 & [name = A] A \\
\ncsubset{A}{B}\ncsubset{A}{D}
\ncsubset{B}{C}\ncsubset{D}{C}
\end{psmatrix} \]

\end{document} 

Answer 4

I've been reading about 'partway modifiers' in the TikZ documentation:

\documentclass[tikz]{standalone}
\usetikzlibrary{calc}

\newcommand{\rotsym}[1]{%
    \rotatebox{#1}{$\subseteq$}%
}

\begin{document}

\begin{tikzpicture}
\node (a) at (0,0) {A};
\node (b) at (.75,.75) {B};
\node (c) at (1.5,0) {C};
\node (d) at (.75,-.75) {D};
%% TikZ documentation section 13.5.3:
\node at ($(a)!0.5!(b)$) {\rotsym{45}};
\node at ($(b)!0.5!(c)$) {\rotsym{315}};
\node at ($(c)!0.5!(d)$) {\rotsym{45}};
\node at ($(d)!0.5!(a)$) {\rotsym{315}};
\end{tikzpicture}

\end{document}

There may be more compact ways of doing this, but I like the clarity and editability of this. YMMV.